Flagellar Synthesis in Salmonella typhimurium: Factors Affecting the Formation of the Flagellar -N-Methyllysine

Abstract

In growing cultures of S typhimurium, flagellar [SIGMA] -N-methyllysine (NML) can be isotopically labelled with either L-[ Me-C14 ] methionine or L- [ U-C14 ] lysine. This isotopic labelling of flagellar NML was unaffected by the addition of DL-NML to the incubation medium. The methionine analogues, D-methionine and DL-ethionine, competitively inhibited the incorporation of the methyl group from methionine into flagellar NML, but had no effect on the incorporation of L- [U-C14] lysine. Although it is probable that methylation of lysine occurs after it has been incorporated into the flagellin molecule, it has not been possible by using antibiotics and purine and pyrimidine analogues to differentiate between flagellar synthesis and the formation of flagellar NML. Attempts to obtain a cell-free preparation capable of synthesizing NML have so far been unsuccessful.