In vivo methylation of prokaryotic elongation factor Tu.
In Salmonella typhimurium and Escherichia coli, elongation factor Tu (EF-Tu) is methylated as shown by its incorporation of labeled methyl residues from [methyl-3H]methionine. Analysis of the nature of the methyl-containing residues by protein hydrolysis, followed by paper chromatography and high voltage electrophoresis showed that both mono- and dimethyllysine are present. Eighty per cent of the EF-Tu molecules are methylated if methylation occurs at a unique lysine residue. The EF-Tu fraction which is not methylated is still able to accept methyl groups, as shown by methylation of approximately 10% of the EF-Tu after addition of chloramphenicol (D-(-)-threo-2,2-dichloro-N-[beta-hydroxy-alpha-(hydroxymethyl)-o-nitrophenethyl] acetamide) to inhibit further protein synthesis. There is no evidence of turnover of the methyl residues. We attempted to separate the methylated from the nonmethylated form of EF-Tu by isoelectric focusing on polyacrylamide gel, but were unable to do so.
D002701:Chloramphenicol / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D008715:Methionine / Q000378:metabolism; D008745:Methylation; D010445:Peptide Elongation Factors / Q000378:metabolism*; D012486:Salmonella typhimurium / Q000378:metabolism*
D010445:Peptide Elongation Factors; D002701:Chloramphenicol; D008715:Methionine