Inhibition of lipopolysaccharide O-antigen synthesis by colicin M.
Colicin M inhibits peptidoglycan biosynthesis at the level of the bactoprenyl carrier lipid. Since the synthesis of O-antigen also requires bactoprenyl carrier lipid, the effect of colicin M on O-antigen biosynthesis was studied using a colicin-sensitive strain of Salmonella typhimurium. Determination of O-antigen intermediates by two different methods showed that bactoprenyl-dependent O-antigen biosynthesis was inhibited by colicin M. Synthesis of both O-antigen and peptidoglycan was almost immediately inhibited following colicin addition. This was followed some 20 min later by cell lysis. The only known common step between O-antigen and peptidoglycan synthesis is formation of bactoprenyl phosphate by dephosphorylation of bactoprenyl pyrophosphate. Determination of bactoprenyl phosphates showed an accumulation of bactoprenyl pyrophosphate in colicin-treated cultures. It was concluded that dephosphorylation of the bactoprenyl lipid carrier was inhibited by colicin M, and this in turn prevented both O-antigen and peptidoglycan synthesis.
Harkness
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Mikrobiologie II, Universität Tübingen, Federal Republic of Germany.
Braun
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D000942:Antigens, Bacterial / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D003087:Colicins / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D008826:Microbial Sensitivity Tests; D019081:O Antigens; D010457:Peptidoglycan / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D011106:Polyisoprenyl Phosphates / Q000032:analysis; D012486:Salmonella typhimurium / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
D000942:Antigens, Bacterial; D003087:Colicins; D008070:Lipopolysaccharides; D019081:O Antigens; D010457:Peptidoglycan; D011106:Polyisoprenyl Phosphates