Accuracy of initial codon selection by aminoacyl-tRNAs on the mRNA-programmed bacterial ribosome
2015 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, no 31, 9602-9607 p.Article in journal (Refereed) Published
We used a cell-free system with pure Escherichia coli components to study initial codon selection of aminoacyl-tRNAs in ternary complex with elongation factor Tu and GTP on messenger RNA-programmed ribosomes. We took advantage of the universal rate-accuracy trade-off for all enzymatic selections to determine how the efficiency of initial codon readings decreased linearly toward zero as the accuracy of discrimination against near-cognate and wobble codon readings increased toward the maximal asymptote, the d value. We report data on the rate-accuracy variation for 7 cognate, 7 wobble, and 56 near-cognate codon readings comprising about 15% of the genetic code. Their d values varied about 400-fold in the 200-80,000 range depending on type of mismatch, mismatch position in the codon, and tRNA isoacceptor type. We identified error hot spots (d = 200) for U:G misreading in second and U:U or G:A misreading in third codon position by His-tRNA(His) and, as also seen in vivo, Glu-tRNA(Glu). We suggest that the proofreading mechanism has evolved to attenuate error hot spots in initial selection such as those found here.
Place, publisher, year, edition, pages
2015. Vol. 112, no 31, 9602-9607 p.
protein synthesis, genetic code, misreading, error hot spots, kinetics
IdentifiersURN: urn:nbn:se:uu:diva-261240DOI: 10.1073/pnas.1506823112ISI: 000358930600052PubMedID: 26195797OAI: oai:DiVA.org:uu-261240DiVA: diva2:851777
FunderSwedish Research CouncilKnut and Alice Wallenberg Foundation