TY - JOUR
T1 - Biosynthesis of a rare di-N-acetylated sugar in the lipopolysaccharides of both Pseudomonas aeruginosa and Bordetella pertussis occurs via an identical scheme despite different gene clusters
AU - Westman, Erin L
AU - Preston, Andrew
AU - Field, Robert A
AU - Lam, Joseph S
PY - 2008
Y1 - 2008
N2 - Pseudomonas aeruginosa and Bordetella pertussis produce lipopolysaccharide (LPS) that contains 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid (D-ManNAc3NAcA). A five-enzyme biosynthetic pathway that requires WbpA, WbpB, WbpE, WbpD, and WbpI has been proposed for the production of this sugar in P. aeruginosa, based on analysis of genes present in the B-band LPS biosynthesis cluster. In the analogous B. pertussis cluster, homologs of wbpB to wbpI were present, but a putative dehydrogenase gene was missing; therefore, the biosynthetic mechanism for UDP-D-ManNAc3NAcA was unclear. Nonpolar knockout mutants of each P. aeruginosa gene were constructed. Complementation analysis of the mutants demonstrated that B-band LPS production was restored to P. aeruginosa knockout mutants when the relevant B. pertussis genes were supplied in trans. Thus, the genes that encode the putative oxidase, transaminase, N-acetyltransferase, and epimerase enzymes in B. pertussis are functional homologs of those in P. aeruginosa. Two candidate dehydrogenase genes were located by searching the B. pertussis genome; these have 80% identity to P. aeruginosa wbpO (serotype O6) and 32% identity to wbpA (serotype O5). These genes, wbpO(1629) and wbpO(3150), were shown to complement a wbpA knockout of P. aeruginosa. Capillary electrophoresis was used to characterize the enzymatic activities of purified WbpO(1629) and WbpO(3150), and mass spectrometry analysis confirmed that the two enzymes are dehydrogenases capable of converting UDP-D-GlcNAc, UDP-D-GalNAc, to a lesser extent, and UDP-D-Glc, to a much lesser extent. Together, these results suggest that B. pertussis produces UDP-D-ManNAc3NAcA through the same pathway proposed for P. aeruginosa, despite differences in the genomic context of the genes involved.
AB - Pseudomonas aeruginosa and Bordetella pertussis produce lipopolysaccharide (LPS) that contains 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid (D-ManNAc3NAcA). A five-enzyme biosynthetic pathway that requires WbpA, WbpB, WbpE, WbpD, and WbpI has been proposed for the production of this sugar in P. aeruginosa, based on analysis of genes present in the B-band LPS biosynthesis cluster. In the analogous B. pertussis cluster, homologs of wbpB to wbpI were present, but a putative dehydrogenase gene was missing; therefore, the biosynthetic mechanism for UDP-D-ManNAc3NAcA was unclear. Nonpolar knockout mutants of each P. aeruginosa gene were constructed. Complementation analysis of the mutants demonstrated that B-band LPS production was restored to P. aeruginosa knockout mutants when the relevant B. pertussis genes were supplied in trans. Thus, the genes that encode the putative oxidase, transaminase, N-acetyltransferase, and epimerase enzymes in B. pertussis are functional homologs of those in P. aeruginosa. Two candidate dehydrogenase genes were located by searching the B. pertussis genome; these have 80% identity to P. aeruginosa wbpO (serotype O6) and 32% identity to wbpA (serotype O5). These genes, wbpO(1629) and wbpO(3150), were shown to complement a wbpA knockout of P. aeruginosa. Capillary electrophoresis was used to characterize the enzymatic activities of purified WbpO(1629) and WbpO(3150), and mass spectrometry analysis confirmed that the two enzymes are dehydrogenases capable of converting UDP-D-GlcNAc, UDP-D-GalNAc, to a lesser extent, and UDP-D-Glc, to a much lesser extent. Together, these results suggest that B. pertussis produces UDP-D-ManNAc3NAcA through the same pathway proposed for P. aeruginosa, despite differences in the genomic context of the genes involved.
UR - http://www.scopus.com/inward/record.url?scp=51549111375&partnerID=8YFLogxK
UR - http://dx.doi.org/10.1128/JB.00579-08
U2 - 10.1128/JB.00579-08
DO - 10.1128/JB.00579-08
M3 - Article
C2 - 18621892
VL - 190
SP - 6060
EP - 6069
JO - Journal of Bacteriology
JF - Journal of Bacteriology
IS - 18
ER -