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  • 1.
    Andersson, Håkan S.
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Ramström, Olof
    Lund University.
    Crown ethers as a tool for the preparation of molecularly imprinted polymers1997Conference paper (Other academic)
  • 2. Andre, Sabine
    et al.
    Pei, Zichao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Siebert, Hans-Christian
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Gabius, Hans-Joachim
    Glycosyldisulfides from Dynamic Combinatorial Libraries as O-Glycoside Mimetics for Plant and Endogenous Lectins: Their Reactivities in Solid-Phase and Cell Assays and Conformational Analysis by Molecular Dynamics Simulations2006In: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, Vol. 14, p. 6314-6326Article in journal (Refereed)
    Abstract [en]

    Dynamic combinatorial library design exploiting the thiol-disulfide exchange readily affords access to glycosyldisulfides. In order to reveal lectin-binding properties of this type of non-hydrolyzable sugar derivative, libraries originating from a mixture of common building blocks of natural glycans and thiocompounds were tested against three plant agglutinins with specificity to galactose, fucose or N-acetylgalactosamine, respectively, in a solid-phase assay. Extent of lectin binding to matrix-immobilized neoglycoprotein presenting the cognate sugar could be reduced, and evidence for dependence on type of carbohydrate was provided by dynamic deconvolution. Glycosyldisulfides also maintained activity in assays of increased physiological relevance, that is, using native tumor cells and also adding to the test panel an endogenous lectin (galectin-3) involved in tumor spread and cardiac dysfunction. N-Acetylgalactosamine was pinpointed as the most important building block of libraries for the human lectin and the digalactoside as most potent compound acting on the toxic mistletoe agglutinin which is closely related to the biohazard ricin. Because this glycosyldisulfide, which even surpasses lactose in inhibitory capacity, rivals thiodigalactoside as inhibitor, their degrees of intramolecular flexibility were comparatively analyzed by computational calculations. Molecular dynamics runs with explicit consideration of water molecules revealed a conspicuously high degree of potential for shape alterations by the disulfide's three-bond system at the interglycosidic linkage. The presented evidence defines glycosyldisulfides as biologically active ligands for lectins

  • 3.
    Angelin, Marcus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fischer, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Crystallization-induced secondary selection from a tandem driven dynamic combinatorial resolution process2008In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 73, no 9, p. 3593-3595Article in journal (Refereed)
    Abstract [en]

    Crystallization-induced secondary selection from a tandem driven dynamic combinatorial library is presented. In a one-pot experiment, an initial nitroaldol equilibrium was kinetically driven by a tandem reaction resulting in a subsequent dynamic library of diastereoisomers. This library was then further driven by a phase change, resulting in amplification and isolation of a highly diastereomerically enriched and synthetically interesting isoindolinone.

  • 4.
    Angelin, Marcus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Larsson, Rikard
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Vongvilai, Pornrapee
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Introducing Dynamic Combinatorial Chemistry: Probing the Substrate Selectivity of Acetylcholinesterase2010In: Journal of Chemical Education, ISSN 0021-9584, E-ISSN 1938-1328, Vol. 87, no 11, p. 1248-1251Article in journal (Refereed)
  • 5.
    Angelin, Marcus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Rahm, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Fischer, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Diastereoselective One-Pot Tandem Synthesis of 3-Substituted Isoindolinones: A Mechanistic Investigation2010In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 75, no 17, p. 5882-5887Article in journal (Refereed)
    Abstract [en]

    The mechanism of a base-catalyzed one-pot reaction of 2-cyanobenzaldehyde and primary nitroalkanes, to produce 3-substituted isoindolinones, has been investigated. A route starting with a nitroaldol (Henry) reaction, followed by a subsequent cyclization and rearrangement, was supported by intermediate analogue synthesis and DFT calculations. Direct diastereoselective crystallization from the reaction mixture was also achieved and studied for a number of substrates. Furthermore, the 3-substituted isoindolinones are an interesting group of compounds, both present important natural products, as well as being precursors to other valuable building blocks.

  • 6.
    Deng, Lingquan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Norberg, Oscar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Uppalapati, Suji
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Stereoselective synthesis of light-activatable perfluorophenylazide-conjugated carbohydrates for glycoarray fabrication and evaluation of structural effects on protein binding by SPR imaging2011In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 9, no 9, p. 3188-3198Article in journal (Refereed)
    Abstract [en]

    A series of light-activatable perfluorophenylazide (PFPA)-conjugated carbohydrate structures have been synthesized and applied to glycoarray fabrication. The glycoconjugates were structurally varied with respect to anomeric attachment, S-, and O-linked carbohydrates, respectively, as well as linker structure and length. Efficient stereoselective synthetic routes were developed, leading to the formation of the PFPA-conjugated structures in good yields over few steps. The use of glycosyl thiols as donors proved especially efficient and provided the final compounds in up to 70% total yield with high anomeric purities. PFPA-based photochemistry was subsequently used to generate carbohydrate arrays on a polymeric surface, and surface plasmon resonance imaging (SPRi) was applied for evaluation of carbohydrate-protein interactions using the plant lectin Concanavalin A (Con A) as a probe. The results indicate better performance and equal efficiency of S-and O-linked structures with intermediate linker length.

  • 7.
    Deng, Lingquan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Wang, Xin
    Uppalapati, Suji
    Norberg, Oscar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Dong, Hai
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Joliton, Adrien
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Stereocontrolled 1-S-glycosylation and comparative binding studies of photoprobe-thiosaccharide conjugates with their O-linked analogs2013In: Pure and Applied Chemistry, ISSN 0033-4545, E-ISSN 1365-3075, Vol. 85, no 9, p. 1789-1801Article in journal (Refereed)
    Abstract [en]

    The use of thioglycosides and other glycan derivatives with anomeric sulfur linkages is gaining increasing interest, both in synthesis and in various biological contexts. Herein, we demonstrate the occurrence and circumvention of anomerization during 1-S-glycosylation reactions, and present highly efficient and stereocontrolled syntheses of a series of photoprobe-thiosaccharide conjugates. Mutarotation of glycosyl thiols proved to be the origin of the anomeric mixtures formed, and kinetic effects could be used to circumvent anomerization. The synthesized carbohydrate conjugates were then evaluated by both solution- and solid-phase-based techniques. Both binding results showed that the S-linked glycosides interact with their cognate lectins comparably to the corresponding O-analogs in the present cases, thus demonstrating the reliability of the solid-support platform built upon our photo-initiated carbohydrate immobilization method for probing protein bindings, and showing the potential of combining these two means for studying carbohydrate-protein inter-actions.

  • 8.
    Dong, Hai
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Deng, Lingquan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Control of the Ambident Reactivity of the Nitrite Ion inCarbohydrate EpimerizationManuscript (Other academic)
  • 9.
    Dong, Hai
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Pei, Zhichao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Angelin, Marcus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Byström, Styrbjörn
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Efficient Synthesis of β-D-Mannosides and β-D-Talosides by Double Parallel or Double Serial Inversion2007In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 72, no 10, p. 3694-3701Article in journal (Refereed)
    Abstract [en]

    A neighboring equatorial ester group plays a highly important role in the Lattrell-Dax (nitrite-mediated) carbohydrate epimerization reaction, inducing the formation of inversion compounds in good yields. On the basis of this effect, efficient synthetic routes to beta-D-mannosides and beta-D-talosides, from the corresponding beta-D-galactosides and beta-D-glucosides, have been designed. The present routes are based on multiple regioselective acylation via the respective stannylene intermediates, followed by inversions to the corresponding manno- and talopyranoside structures by nitrite or acetate substitution. It was found that the ester group was able to induce the inversion of its two neighboring groups in high yields following either a double parallel or a double serial inversion process. By combination of direct inversion, and neighboring- as well as remote-group participation, several beta-D-mannoside and beta-D-taloside derivatives were very conveniently obtained in good yields.

  • 10.
    Dong, Hai
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Pei, Zhichao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Byström, Styrbjörn
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Reagent-dependent regioselective control in multiple carbohydrate esterifications2007In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 72, no 4, p. 1499-1502Article in journal (Refereed)
    Abstract [en]

    Regioselective control in organotin-mediated multiple acylation of carbohydrates is presented. The acylation reagent could be efficiently used to direct the product formation. Reagent-dependent thermodynamic and kinetic control and dynamic assistance mechanisms are suggested, resulting in the efficient preparation of building blocks that normally require many steps with traditional synthesis.

  • 11.
    Dong, Hai
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Pei, Zhichao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Stereospecific Ester Activation in Nitrite-Mediated Carbohydrate Epimerization2006In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 71, no 8, p. 3306-3309Article in journal (Refereed)
    Abstract [en]

    The Lattrell-Dax method of nitrite-mediated substitution of carbohydrate triflates is an efficient method to generate structures of inverse configuration. In the present study, epimerization of gluco- and galactopyranoside derivatives to the corresponding allo- and gulopyranoside structures by triflation/nitrite treatment has been investigated. It was found that a neighboring ester group was essential for the reactivity of the nitrite-mediated triflate, inversion. Furthermore, a good inversion yield also depended on the relative configuration of the neighboring ester group to the triflate. Only with the ester group in the equatorial position, whatever the configuration of the triflate, did the reaction proceed smoothly, whereas a neighboring axial ester group proved largely inefficient. The results were subsequently used to predict the inversion of glucopyranoside derivatives to the mannopyranoside epimers.

  • 12.
    Dong, Hai
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Pei, Zhichao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Supramolecular activation in triggered cascade inversion2008In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, p. 1359-1361Article in journal (Refereed)
    Abstract [en]

    An unexpected activation effect from combinations of anionic reagent and amine base resulted in dramatic rate enhancements in multiple carbohydrate cascade inversion.

  • 13.
    Dong, Hai
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Rahm, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Supramolecular Control in Carbohydrate Epimerization: Discovery of a New Anion Host−Guest System2008In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 130, p. 15270-15271Article in journal (Refereed)
    Abstract [en]

    A new anion-carbohydrate recognition system is described. Pyranosides with axial protons in 1-, 3-, and 5-position proved efficient, forming relatively strong complexes between the anion and the B-face of the carbohydrate. This system could furthermore be used in supramolecular control in Lattrell-Dax epimerization reactions, leading to either activation or deactivation effects.

  • 14.
    Dong, Hai
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Enhanced Basicity by Supramolecular Anion ActivationManuscript (Other academic)
  • 15.
    Hu, Lei
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Silver-catalyzed dynamic systemic resolution of alpha-iminonitriles in a 1,3-dipolar cycloaddition process2014In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 50, no 29, p. 3792-3794Article in journal (Refereed)
    Abstract [en]

    A dynamic azomethine ylide system was established using Sc(OTf)(3) and Ag/Taniaphos as catalysts. The system was subsequently kinetically resolved in a tandem 1,3-dipolar cycloaddition process where the silver complex acted as both a reaction catalyst and an external selector, resulting in the formation of an exclusive pyrrolidine product in good yield and enantiopurity.

  • 16.
    Hu, Lei
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ren, Yansong
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Chirality Control in Enzyme-Catalyzed Dynamic Kinetic Resolution of 1,3-Oxathiolanes2015In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 80, no 16, p. 8478-8481Article in journal (Refereed)
    Abstract [en]

    The origin of enantioenrichment in enzyme-catalyzed dynamic kinetic resolution of 1,3-oxathiolane derivatives, key intermediates for asymmetric lamivudine synthesis, was elucidated. The chirality control could be determined by chiral HPLC and NOE NMR spectroscopy using a modified 1,3-oxathiolane compound obtained through enzyme-catalyzed selective hydrolysis. Solvent-dependent stereoselectivity was observed under biphasic conditions using different organic solvents with phosphate buffer.

  • 17.
    Hu, Lei
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhang, Yan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lipase-catalyzed asymmetric synthesis of oxathiazinanones through dynamic covalent kinetic resolution2014In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 12, no 22, p. 3572-3575Article in journal (Refereed)
    Abstract [en]

    A domino addition-lactonization pathway has been applied to a dynamic covalent resolution protocol, leading to efficient oxathiazinanone formation as well as chiral discrimination. A new, double biocatalytic pathway has furthermore been proposed and evaluated where the initial product inhibition could be efficiently circumvented.

  • 18.
    Kong, Na
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Joen, Seaho
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Covalent Functionalization of Buckminsterfullerene with Perfluorophenyl Azide by Microwave Irradiation, Photochemical or Thermal ActivationManuscript (preprint) (Other academic)
  • 19.
    Kong, Na
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Park, JaeHyeung
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Carbohydrate Functionalization of Few-Layer Graphene through Microwave-Assisted Reaction of Perfluorophenyl AzideManuscript (preprint) (Other academic)
  • 20.
    Kong, Na
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhou, Juan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Park, JaeHyeung
    University of Massachusetts, United States .
    Xie, Sheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. University of Massachusetts, United States .
    Metal-Free Carbohydrate Immobilization on Nanoparticles Using Perfluorophenyl Azide-Based Azide-Aldehyde-Amine CycloadditionManuscript (preprint) (Other academic)
  • 21.
    Kong, Na
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhou, Juan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Park, JaeHyeung
    University of Massachusetts, United States .
    Xie, Sheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. University of Massachusetts, United States .
    Quantitative Fluorine NMR To Determine Carbohydrate Density on Glyconanomaterials Synthesized from Perfluorophenyl Azide-Functionalized Silica Nanoparticles by Click Reaction2015In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 87, no 18, p. 9451-9458Article in journal (Refereed)
    Abstract [en]

    A quantitative fluorine NMR (F-19 qNMR) method was developed to determine the carbohydrate density on glyconanomaterials. Mannose (Man)- and galactose (Gal)-conjugated silica nanoparticles (SNPs) were synthesized from perfluorophenyl azide (PFPA)-functionalized SNPs and propargylated Man or Gal by copper-catalyzed azide-alkyne cycloaddition (click reaction). After treating PFPA-SNPs or Man-SNPs with hydrofluoric acid followed by lyophilization, the remaining residues were directly subjected to F-19 NMR analysis. The density of PFPA on PFPA-SNP was determined to be 7.7 +/- 0.2 x 10(-16) nmol/nm(2) and Man on Man-SNP to be 6.4 +/- 0.2 x 10(-16) nmol/nm(2) giving a yield of similar to 83% for the click coupling reaction. The apparent dissociation constant (K-d) of Man-SNPs with fluorescein isothiocyanate(FITC)-concanavalin A (Con A) was determined using a fluorescence competition assay to be 0.289 +/- 0.003 mu M, which represents more than 3 orders of magnitude affinity increase compared to free Man with Con A.

  • 22.
    Larsson, Rikard
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Albers, Antonia
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Simons, Adrian
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Tandem Driven Dynamic Self-Inhibition of AcetylcholinesteraseManuscript (Other academic)
  • 23.
    Larsson, Rikard
    et al.
    KTH, Superseded Departments, Chemistry.
    Pei, Zhichao
    KTH, Superseded Departments, Chemistry.
    Ramström, Olof
    KTH, Superseded Departments, Chemistry.
    Catalytic Self-Screening of Cholinesterase Substrates from a Dynamic Combinatorial Thioester Library2004In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 43, no 28, p. 3716-3718Article in journal (Refereed)
    Abstract [en]

    Simply the best: Dynamic combinatorial chemistry coupled to enzyme catalysis was used to identify enzyme substrates in a library constructed from a series of thioesters and thiols by transesterification. The library was directly coupled to the catalytic action of acetylcholinesterase, which selectively hydrolyzed the best substrate candidates (see schematic representation). The process allowed rapid identification of discrete substrates.

  • 24.
    Larsson, Rikard
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Dynamic Combinatorial Thiolester Libraries for Efficient Catalytic Self-Screening of Hydrolase Substrates2006In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 1, p. 285-291Article in journal (Refereed)
    Abstract [en]

    Dynamic combinatorial thiolester libraries were efficiently generated from pools of thiols and acyl functionalities through reversible transthiolesterification in aqueous media at neutral pH. The dynamic features of the library generation were investigated, and the libraries were screened against acetylcholinesterase, clearly demonstrating the catalytic self-screening of its substrates from the constituents. Acetyl- and propionylthiocholine were easily identified as the best substrates for the enzyme, whereas other constituents showed lower efficiency or were inactive. A range of hydrolases was furthermore screened for rapid substrate identification, clearly demonstrating the differences in selectivity. The results show that transthiolesterification is a useful method to generate dynamic libraries, and that the catalytic self -screening concept is highly valuable for substrate identification.

  • 25. Madwar, Carolin
    et al.
    Kwan, William Chu
    Deng, Lingquan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Schmidt, Rolf
    Zou, Shan
    Cuccia, Louis A.
    Perfluorophenyl Azide Immobilization Chemistry for Single Molecule Force Spectroscopy of the Concanavalin A/Mannose Interaction2010In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, no 22, p. 16677-16680Article in journal (Refereed)
    Abstract [en]

    The versatility of perfluorophenyl azide (PFPA) derivatives makes them useful for attaching a wide variety of biomoleculcs and polymers to surfaces. Herein, it single molecule force spectroscopy (SMFS) study of the concanavalin A/mannose interaction was carried out using PFPA immobilization chemistry. SMFS of the concanavalin A/mannose interaction yielded in average unbinding force of 70-80 pN for loading rates between 8000 and 40 000 pN/s for mannose surfaces on aminated glass. and an unbinding force of 57 +/- 20 pN at 6960 pN/s for mannose surfaces on gold-coated glass. Dynamic force spectroscopy was used to determine the dissociation rate constant, k(off), for this interaction to be 0.16 s(-1).

  • 26.
    Neranon, Kitjanit
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Rapid, regioselective deuteration of dimethyl-2,2'-bipyridines via microwave-assistance2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, p. 2684-2688Article in journal (Refereed)
    Abstract [en]

    Isotopically pure [D6]-dimethyl-2,2′-bipyridine derivatives were selectively and rapidly formed using microwave-assisted regioselective deuteration of the methyl moieties of the parent bipyridine in a deuterium oxide solution. For instance, [D6]-4,4′-dimethyl-2,2′-bipyridine was formed in quantitative yield within 15 minutes, in a simple and convenient process.

  • 27.
    Neranon, Kitjanit
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Hao, Nanjing
    University of Massachusetts, United States..
    Chen, Xuan
    University of Massachusetts, United States..
    Manuguri, Sesha
    University of Auckland, Auckland.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ciprofloxacin-presenting Liposomes for Enhanced Antibacterial ActivityManuscript (preprint) (Other academic)
  • 28.
    Neranon, Kitjanit
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Constitutional Dynamics of Bipyridine-Metal Complex SystemsManuscript (preprint) (Other academic)
  • 29.
    Neranon, Kitjanit
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Design, Synthesis and Self-Assembly of Functional Amphiphilic Dendrimers and MetallodendrimersManuscript (preprint) (Other academic)
  • 30.
    Neranon, Kitjanit
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, OlofKTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Self-Assembly of Supramolecular Capsules Based on FeII-Dendrimer Complexes2014Conference proceedings (editor) (Other academic)
  • 31.
    Neranon, Kitjanit
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Stimuli-Responsive, Multivalent Glycodendrimer/Metalloglycodendrimer Assemblies for Targeted DeliveryManuscript (preprint) (Other academic)
  • 32.
    Neranon, Kitjanit
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Åslund, Mattias
    Draupner Innovations, Årsta, Sweden.
    Karalius, Antanas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Min
    Xu, Hao
    KTH, School of Engineering Sciences (SCI), Applied Physics. Department of Applied Physics, Science for Life Laboratory.
    Fu, Ying
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Petermann, Ingemar
    Nanoelectronics, Acreo Swedish ICT AB, Kista, Sweden.
    Björk, Per
    Nanoelectronics, Acreo Swedish ICT AB, Kista, Sweden.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Laser-induced, Surface Plasmon-enhanced Two-photon Excitation for Efficient Chemical Functionalization of Nanostructured Gold SurfacesManuscript (preprint) (Other academic)
  • 33.
    Norberg, Oscar
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fauquet, Germain
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Saur, Ann-Kathrin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Aastrup, Teodor
    Attana AB.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Synthesis and Binding Affinity Analysis of α1-2- and α1-6-O/S-linked Dimannosides for the Elucidation of Sulfur in Glycosidic Bonds using Quartz Crystal Microbalance SensorsArticle in journal (Other academic)
    Abstract [en]

    Synthetic routes towards α1-2- and α1-6-linked dimannosides with S- or O-glycosidic bonds are presented. A glycosylation method was developed in which a sulfhydryl glycosyl acceptor was coupled to a 1-O-acetyl-glycosyl donor under Lewis acid catalysis. Final debenzylation of the S-linked dimannosides were accomplished through Birch reduction in high yields. The protein recognition properties of the synthesized dimannosides were then evaluated in a competition binding assay with the model lectin Con A, to investigate the effect of sulfur in the glycosidic bonds. Mannose-presenting surfaces were produced according to a previously reported Photo-Click immobilization method and the subsequent binding study was performed in an automated QCM flow through instrumentation. The recorded EC50-values correlated well to previously reported binding affinities for the O-linked dimannosides. Results were in agreement with known binding affinities, where the S-analogs displayed slightly weaker binding and a positive apparent cooperativity.

  • 34.
    Pei, Zhichao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Aastrup, Teodor
    Anderson, Henrik
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Redox-Responsive and Calcium-Dependent Switching of Glycosyldisulfide Interactions with Concanavalin A2005In: Bioorganic & Medicinal Chemistry Letters, ISSN 0960-894X, E-ISSN 1090-2120, Vol. 15, p. 2707-2710Article in journal (Refereed)
    Abstract [en]

    Glycosyldisulfides can interact efficiently with carbohydrate-binding entities. This has been shown for a range of thiosaccharide dimers when tested for their effects against the lectin Concanavalin A using a modified quartz crystal microbalance-technique. Contrary to the thiosaccharide monomers, showing no significant binding up to 10 mM, several of the dimers showed IC50-values in the low millimolar range. Three of the glycosyldisulfides tested also displayed very high positive apparent cooperativity effects that were found to be both calcium-dependent and redox-responsive.

  • 35.
    Pei, Zhichao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Andersson, Henrik
    Aastrup, Teodor
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Study of Real-time Lectin–Carbohydrate Interactions on the Surface of a Quartz Crystal Microbalance2005In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 21, no 1, p. 60-66Article in journal (Refereed)
    Abstract [en]

    A quartz crystal microbalance (QCM) biosensor system for lectin-carbohydrate interactions has been developed. Yeast mannan was immobilised on polystyrene-coated quartz crystals, and interactions tested with the lectin concanavalin A (Con A). The biosensor could be easily operated, where mannan immobilisation and all binding analyses were performed in real-time using a flow-through system. The apparent binding constant for yeast mannan to Con A was estimated to be 0.4 μM, well in accordance to reported literature values. In addition, the effective concentration values (EC50-values) for a series of mannose/mannoside ligands, acting as competitors to the mannan/Con A interaction, were determined to range from 0.18 to 5.3 mM, in good correlation with a related enzyme-labelled lectin assay (ELLA) protocol

  • 36.
    Pei, Zhichao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Dong, Hai
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Caraballo, Rémi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Synthesis of Positional Thiol Analogs of β-D-Galactopyranose2007In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 29, p. 4927-4934Article in journal (Refereed)
    Abstract [en]

    Approaches toward the synthesis of thio- beta -D -galactose derivatives are described. These compounds were prepared from the parent carbohydrates: D-galactose, methyl P-D-galactoside and methyl P-D-glucoside, respectively. It was found that not only the strategies of protecting group introduction and selective deprotection, but also the choices of solvent and nucleophilic reagent concentration were crucial to allow the efficient introduction of sulfur at different positions of the galactose ring. The effects from the solvent, the nucleophilic reagent concentration, and the protecting group patterns have been investigated. The results clearly show that ester protecting groups play highly important roles for the synthesis of thio-containing carbohydrates, requiring nonpolar solvents to suppress the neighboring group participation. For the Lattrell-Dax (nitrite -mediated) inversion reaction, employed in the synthetic route to the 2-thio-beta-D-galactoside, intramolecular nucleophilic attack, as well as stronger stereospecific ester activation, are necessary to overcome hindrance from 4,6-O-benzylidene protection.

  • 37.
    Pei, Zhichao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Dong, Hai
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Solvent-dependent, kinetically controlled stereoselective synthesis of 3- and 4- thioglycosides2005In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 70, no 17, p. 6952-6955Article in journal (Refereed)
    Abstract [en]

    Facile approaches to prepare 3- and 4-thioglycosides of the galacto, gulo, and gluco type from the parent triflates are presented. The dependencies of the solvent and the protecting group pattern, as well as the configuration of the neighboring and leaving groups, have been studied for these reactions. The results clearly show that the efficient stereo-selective synthesis of methyl 3-thin-galactoside depends highly on the solvent and the nucleophile concentration.

  • 38.
    Pei, Zhichao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Larsson, Rikard
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Aastrup, Teodor
    Attana AB.
    Anderson, Henrik
    Uppsala University, Ångström Laboratory, Solid State Electronics.
    Lehn, Jean-Marie
    ISIS-Université Louis Pasteur.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Quartz crystal microbalance bioaffinity sensor for rapid identification of glycosyldisulfide lectin inhibitors from a dynamic combinatorial library2006In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 22, no 1, p. 42-48Article in journal (Refereed)
    Abstract [en]

    Carbohydrate-lectin,interactions were probed with dynamic combinatorial libraries, using the plant lectin Concanavalin A as target species. The dynamic combinatorial libraries were generated from a pool of thiol components through reversible thiol-disulfide interchange, and screened using a simple and efficient method based on a quartz crystal microbalance setup. It was found that dimers based on 1-thio- and 6-thin-mannose analogues were the most active inhibitors. Furthermore, the results clearly show that the 6-thio-mannose possess unique characteristics compared to its oxygen-containing counterpart.

  • 39.
    Pei, Zhichao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Pei, Yuxin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Yu, Hui
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Theurer, Matthias
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    André, Sabine
    Gabius, Hans-Joachim
    Yan, Mingdi
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Photoderivatized QCM Surfaces for the Study of Real-Time Lectin-Carbohydrate InteractionsArticle in journal (Refereed)
  • 40.
    Sakulsombat, Morakot
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Angelin, Marcus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Tandem reversible addition-intramolecular lactonization for the synthesis of 3-functionalized phthalides2010In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, no 1, p. 75-78Article in journal (Refereed)
    Abstract [en]

    A new tandem process based on reversible nucleophilic addition and intramolecular lactonization of methyl 2-formylbenzoate leads to the efficient synthesis of 3-functionalized phthalides, which are important precursors for the synthesis of quinone skeletons via Hauser–Kraus annulation. The reactions are successfully carried out under mild conditions in single operations.

  • 41.
    Sakulsombat, Morakot
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Vongvilai, Pornrapee
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    In Situ Evaluation of Lipase Performances Through Dynamic Asymmetric Cyanohydrin Resolution2011In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 9, no 4, p. 1112-1117Article in journal (Refereed)
    Abstract [en]

    A dynamic resolution process based on multiple reversible cyanohydrin formation coupled to lipase-mediated transesterification is demonstrated. The resulting process resulted in the efficient evaluation of complex lipase performances in asymmetric cyanohydrin acylate synthesis. Dynamic systems were generated and resolved in situ, and the effects of the reaction conditions could be directly monitored for the overall system. By this concept, the enzyme activity, chemo- and stereoselectivity for all involved substrates could be simultaneously evaluated.

  • 42.
    Schaufelberger, Fredrik
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Programmed Error-Correction within Dynamic Catalyst Systems for the Morita-Baylis-Hillman reactionManuscript (preprint) (Other academic)
    Abstract [en]

    The understanding of complex reaction networks of small molecules with emergent systemic functionality is integral to both systems chemistry and origin-of-life studies. In this work, a dynamic catalytic system of nucleophilic catalysts for the Morita-Baylis-Hillman (MBH) reaction is demonstrated, exhibiting self-resolution behavior along with thermodynamically driven error-correction. A class of readily reversible MBH adducts from substrates with internal H-transfer capabilities is furthermore presented, displaying rate accelerations of retro-MBH reactions up to 10 000 times. The retro-MBH reaction was used as a design element in a self-resolving dynamic catalytic system, yielding a transient product that was eventually transformed into a more stable thermodynamic product. This study demonstrates efficient self-sorting of complex small molecular catalytic systems.

  • 43.
    Schaufelberger, Fredrik
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Seigel, Karolina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Biomimetic Hydrogen Bonding Catalysis of Imine Exchange for Rapid Equilibration of Dynamic SystemsManuscript (preprint) (Other academic)
    Abstract [en]

    The reversibility of imine bonds has been exploited to great effect in the field of dynamic covalent chemistry, for example in the preparation of dynamic systems for a wide variety of applications. However, acid catalysis is commonly needed for efficient equilibration of imine mixtures. Herein, it is demonstrated that hydrogen bond donors, such as thioureas and squaramides, can catalyze the equilibration of dynamic imine systems under unprecedentedly mild conditions. Catalysis occurs in a range of solvents and in the presence of many sensitive additives, showing moderate to good rate accelerations for both imine metathesis and transimination with amines, hydrazines and hydroxylamines. Furthermore, the catalyst proved simple to immobilize, introducing both reusability and extended control of the equilibration process.

  • 44.
    Schaufelberger, Fredrik
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Timmer, Brian J. J.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Resolving a Reactive Organometallic Intermediate from Dynamic Directing Group Systems by Selective C-H ActivationManuscript (preprint) (Other academic)
    Abstract [en]

    Catalyst discovery from systems of potential precursors is a challenging endeavor. Herein, a new strategy applying dynamic chemistry to the identification of catalyst precursors from C-H activation of imines is proposed and evaluated. Using hydroacylation of imines as a model reaction, the selection of an organometallic reactive intermediate from a dynamic imine system, involving many potential directing group/metal entities, is demonstrated. The identity of the amplified reaction intermediate with the best directing group could be resolved in situ via ESI-MS, and coupling of the procedure to an iterative deconvolution protocol generated a system with high screening efficiency.

  • 45.
    Timmer, Brian J.J.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Flos, M. Abellán
    Altun, Samuel
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Aastrup, Teodor
    Vincent, Stéphane
    Key Factors for Multivalency Effects in Carbohydrate Nanoplatform-Lectin InteractionsManuscript (preprint) (Other academic)
  • 46.
    Timmer, Brian J.J.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kravchenko, Oleksandr
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Selective Cross Metathesis of Highly Functionalized Substrates in Aqueous MediaManuscript (preprint) (Other academic)
  • 47.
    Timmer, Brian J.J.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Acid-Assisted Direct Olefin Metathesis of Unprotected Carbohydrates in WaterManuscript (preprint) (Other academic)
  • 48.
    Vongvilai, Pornrapee
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Dynamic Asymmetric Multicomponent Resolution: Lipase-Mediated Amidation of a Double Dynamic Covalent System2009In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 131, no 40, p. 14419-14425Article in journal (Refereed)
    Abstract [en]

    The Strecker reaction is one of the most important multicomponent reactions developed, leading to alpha-aminonitriles that are versatile substrates for many synthetic applications. In the present study, this reaction type has been applied to a double dynamic covalent resolution protocol, leading to efficient C-C- and C-N-bond generation as well as chiral discrimination. The combination of transimination with iminecyanation enabled the dynamic exchange in more,than one direction around a single stereogenic center of restricted structure. This multiple exchange process could generate a vast range of compounds from a low number of starting materials in very short time. The resulting double dynamic covalent systems, created under thermodynamic control, were subsequently coupled in a one-pot process with kinetically controlled lipase-mediated transacylation. This resulted in complete resolution of the dynamic systems, yielding the optimal N-acyl-alpha-aminonitriles for the enzyme, where the individual chemoenzymatic reactions could produce enantiomerically pure acylated N-substituted alpha-aminonitriles in good yields.

  • 49.
    Vongvilai, Pornrapee
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Sakulsombat, Morakot
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    In Situ Evaluation of Lipase Performances Through Dynamic Asymmetric Cyanohydrin ResolutionManuscript (preprint) (Other academic)
  • 50. Wang, Xin
    et al.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Quantitative Analysis of Multivalent Ligand Presentation on Gold Glyconanoparticles and the Impact on Lectin Binding2010In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 82, no 21, p. 9082-9089Article in journal (Refereed)
    Abstract [en]

    Glyconanomaterials, nanomaterials carrying multiple carbohydrate ligands, provide an excellent platform for sensitive protein recognition. Using nanomaterials as the scaffold, multivalent interactions between glycan ligands and proteins have been demonstrated. However, the quantitative analysis of the binding affinity of these glyconanomaterials has been lacking. In this Article, we report a new method to measure the binding affinity of glyconanoparticle (GNP)-protein interactions based on a fluorescent competition binding assay, which yielded the apparent dissociation constant (K-d) of GNPs with the interacting protein. Au nanoparticles conjugated with underivatized mono-, oligo-, and polysaccharides were synthesized using our recently developed photocoupling chemistry. The affinities of these GNPs with lectins were measured and were several orders of magnitude higher than the corresponding free ligands with lectins. The effect of ligand display on the binding affinity of GNPs was, furthermore, studied where GNPs of varying linker type, spacer length, ligand density, and nanoparticle size were prepared and K-d values determined. The long spacer linker containing hydrocarbon and ethylene oxide units gave the highest binding affinity as well as assay sensitivity. The binding affinity increased with ligand density in general, showing a drastic increase in affinity at low ligand density. In addition, the affinity enhancement was more pronounced on smaller NPs than the larger ones. These results not only demonstrate that the binding affinity of GNPs is highly influenced by how the ligands are presented on the nanoparticles but also pave the way for tailor-made glyconanomaterials with tunable affinity by way of ligand display.

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