Evidence for N----O acetyl migration as the mechanism for O acetylation of peptidoglycan in Proteus mirabilis.
O-acetylated peptidoglycan was purified from Proteus mirabilis grown in the presence of specifically radiolabelled glucosamine derivatives, and the migration of the radiolabel was monitored. Mild-base hydrolysis of the isolated peptidoglycan (to release ester-linked acetate) from cells grown in the presence of 40 microM [acetyl-3H]N-acetyl-D-glucosamine resulted in the release of [3H]acetate, as detected by high-pressure liquid chromatography. The inclusion of either acetate, pyruvate, or acetyl phosphate, each at 1 mM final concentration, did not result in a diminution of mild-base-released [3H]acetate levels. No such release of [3H]acetate was observed with peptidoglycan isolated from either Escherichia coli incubated with the same radiolabel or P. mirabilis grown with [1,6-3H]N-acetyl-D-glucosamine or D-[1-14C]glucosamine. These observations support a hypothesis that O acetylation occurs by N----O acetyl transfer within the sacculus. A decrease in [3H]acetate release by mild-base hydrolysis was observed with the peptidoglycan of P. mirabilis cultures incubated in the presence of antagonists of peptidoglycan biosynthesis, penicillin G and D-cycloserine. The absence of free-amino sugars in the peptidoglycan of P. mirabilis but the detection of glucosamine in spent culture broths implies that N----O transacetylation is intimately associated with peptidoglycan turnover.
Dupont
C
C
Department of Microbiology, University of Guelph, Ontario, Canada.
Clarke
A J
AJ
D000085:Acetates / Q000032:analysis; D000107:Acetylation; D000117:Acetylglucosamine / Q000378:metabolism*; D000596:Amino Acids / Q000032:analysis; D000606:Amino Sugars / Q000032:analysis; D004926:Escherichia coli / Q000378:metabolism; D010457:Peptidoglycan / Q000378:metabolism*; D011513:Proteus mirabilis / Q000378:metabolism*; D011514:Proteus vulgaris / Q000378:metabolism; D011865:Radioisotope Dilution Technique; D014316:Tritium
D000085:Acetates; D000596:Amino Acids; D000606:Amino Sugars; D010457:Peptidoglycan; D014316:Tritium; D000117:Acetylglucosamine