Inhibition of polypeptide chain initiation in Escherichia coli by elongation factor G.
We have previously reported the isolation from E. coli of a specific inhibitor of polypeptide chain initiation that is rendered ineffective when active aminoacylation of transfer RNA is taking place; this is normally the case during natural messenger RNA translation. Surprisingly, the inhibitory activity appears to be a hitherto unrecognized property of the chain elongation factor G. The following hold for preparations purified for either translocase or inhibitor activity: (1) equal electrophoretic mobility on polyacrylamide gels; (2) equal specific activities for (a) inhibition of initiation, (b) translocation, and (c) ribosome-dependent, uncoupled GTPase; and (3) similar heat sensitivity of translocase and inhibitor activities in a temperature-sensitive E. coli mutant with an altered elongation factor G. Different sites are apparently involved in translocation and inhibition because the former, but not the latter, is sensitive to p-chloromercuribenzoate and fusidic acid.
D000215:Acylation; D001426:Bacterial Proteins / Q000096:biosynthesis*; D002250:Carbon Radioisotopes; D002729:Chloromercuribenzoates / Q000494:pharmacology; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D005672:Fusidic Acid / Q000494:pharmacology; D006358:Hot Temperature; D009154:Mutation; D010442:Peptide Chain Initiation, Translational / Q000187:drug effects*; D010445:Peptide Elongation Factors / Q000302:isolation & purification; D010649:Phenylalanine / Q000378:metabolism; D011072:Poly U / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism*; D014178:Translocation, Genetic
D001426:Bacterial Proteins; D002250:Carbon Radioisotopes; D002729:Chloromercuribenzoates; D010445:Peptide Elongation Factors; D012333:RNA, Messenger; D011072:Poly U; D010649:Phenylalanine; D005672:Fusidic Acid; D012343:RNA, Transfer