An msbB homologue carried in plasmid pO157 encodes an acyltransferase involved in lipid A biosynthesis in Escherichia coli O157:H7.
Escherichia coli O157:H7 carries a chromosomal msbB1 and a plasmid-encoded msbB2 gene. We characterized msbB2 function as a homologue of msbB1 by examination of wild-type organisms and mutant strains that lacked functional msbB1, msbB2, and both msbB1 and msbB2. The msbB double-mutant strain generated pentaacyl lipid A, while the single-mutant strains synthesized hexaacyl lipid A. Complementation with overexpressed msbB2 converted pentaacyl into hexaacyl lipid A in the double-mutant strain. The transcription of both msbB genes occurred simultaneously. Lack of MsbB2 activity slightly increased the microheterogeneity of the lipid A species. These results suggest that the msbB2 gene plays a role not only in the routine generation of fully hexaacylated lipid A but also in suppressing the microheterogeneity of lipid A species, the endotoxic determinant of the organism.
Kim
Sang-Hyun
SH
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Jia
Wenyi
W
Bishop
Russell E
RE
Gyles
Carlton
C
D000217:Acyltransferases / Q000235:genetics* / Q000502:physiology; D000818:Animals; D002874:Chromosome Mapping; D019453:Escherichia coli O157 / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000502:physiology; D005816:Genetic Complementation Test; D008050:Lipid A / Q000032:analysis / Q000096:biosynthesis*; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D016366:Open Reading Frames; D010957:Plasmids; D014158:Transcription, Genetic
D029968:Escherichia coli Proteins; D008050:Lipid A; D000217:Acyltransferases; C097895:MsbB protein, E coli