Bacterial ribosome requires multiple L12 dimers for efficient initiation and elongation of protein synthesis involving IF2 and EF-G
2012 (English)In: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 40, no 5, 2054-2064 p.Article in journal (Refereed) Published
The ribosomal stalk in bacteria is composed of four or six copies of L12 proteins arranged in dimers that bind to the adjacent sites on protein L10, spanning 10 amino acids each from the L10 C-terminus. To study why multiple L12 dimers are required on the ribosome, we created a chromosomally engineered Escherichia coli strain, JE105, in which the peripheral L12 dimer binding site was deleted. Thus JE105 harbors ribosomes with only a single L12 dimer. Compared to MG1655, the parental strain with two L12 dimers, JE105 showed significant growth defect suggesting suboptimal function of the ribosomes with one L12 dimer. When tested in a cell-free reconstituted transcription-translation assay the synthesis of a full-length protein, firefly luciferase, was notably slower with JE105 70S ribosomes and 50S subunits. Further, in vitro analysis by fast kinetics revealed that single L12 dimer ribosomes from JE105 are defective in two major steps of translation, namely initiation and elongation involving translational GTPases IF2 and EF-G. Varying number of L12 dimers on the ribosome can be a mechanism in bacteria for modulating the rate of translation in response to growth condition.
Place, publisher, year, edition, pages
2012. Vol. 40, no 5, 2054-2064 p.
ribosome, translation initiation, L12, IF2, subunit association, protein synthesis
Biochemistry and Molecular Biology
Research subject Biology with specialization in Molecular Biology
IdentifiersURN: urn:nbn:se:uu:diva-157694DOI: 10.1093/nar/gkr1031ISI: 000302019900022PubMedID: 22102582OAI: oai:DiVA.org:uu-157694DiVA: diva2:436760