Biochemical and Structural Characterization of WlbA from Bordetella pertussis and Chromobacterium violaceum: Enzymes Required for the Biosynthesis of 2,3-Diacetamido-2,3-dideoxy-d-mannuronic Acid
- UW
The unusual sugar 2,3-diacetamido-2,3-dideoxy-d-mannuronic acid, or ManNAc3NAcA, has been observed in the lipopolysaccharides of both pathogenic and nonpathogenic Gram-negative bacteria. It is added to the lipopolysaccharides of these organisms by glycosyltransferases that use as substrates UDP-ManNAc3NAcA. Five enzymes are ultimately required for the biosynthesis of UDP-ManNAc3NAcA starting from UDP-N-acetylglucosamine. The second enzyme in the pathway, encoded by the wlba gene and referred to as WlbA, catalyzes the NAD-dependent oxidation of the C-3' hydroxyl group of the UDP-linked sugar. Here we describe a combined structural and functional investigation of the WlbA enzymes from Bordetella pertussis and Chromobacterium violaceum. For this investigation, ternary structures were determined in the presence of NAD(H) and substrate to 2.13 and 1.5 {angstrom} resolution, respectively. Both of the enzymes display octameric quaternary structures with their active sites positioned far apart. The octamers can be envisioned as tetramers of dimers. Kinetic studies demonstrate that the reaction mechanisms for these enzymes are sequential and that they do not require {alpha}-ketoglutarate for activity. These results are in sharp contrast to those recently reported for the WlbA enzymes from Pseudomonas aeruginosa and Thermus thermophilus, which function via ping-pong mechanisms that involve {alpha}-ketoglutarate. Taken together, the results reported here demonstrate that there are two distinct families of WlbA enzymes, which differ with respect to amino acid sequences, quaternary structures, active site architectures, and kinetic mechanisms.
- Research Organization:
- Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
- Sponsoring Organization:
- NIH
- OSTI ID:
- 1026548
- Journal Information:
- Biochemistry-US, Journal Name: Biochemistry-US Journal Issue: (9) ; 03, 2011 Vol. 50; ISSN 0006-2960; ISSN BICHAW
- Country of Publication:
- United States
- Language:
- ENGLISH
Similar Records
Structural and Functional Studies of WlbA: A Dehydrogenase Involved in the Biosynthesis of 2,3-Diacetamido-2,3-dideoxy-d-mannuronic Acid
Molecular Structure of WlbB, a Bacterial N-Acetyltransferase Involved in the Biosynthesis of 2,3-Diacetamido-2,3-dideoxy-d-mannuronic Acid
Chromobacterium violaceum presenting as a surgical emergency
Journal Article
·
Wed Sep 08 00:00:00 EDT 2010
· Biochemistry-US
·
OSTI ID:1002681
Molecular Structure of WlbB, a Bacterial N-Acetyltransferase Involved in the Biosynthesis of 2,3-Diacetamido-2,3-dideoxy-d-mannuronic Acid
Journal Article
·
Wed Sep 08 00:00:00 EDT 2010
· Biochemistry-US
·
OSTI ID:1002679
Chromobacterium violaceum presenting as a surgical emergency
Journal Article
·
Tue Sep 01 00:00:00 EDT 1981
· South. Med. J.; (United States)
·
OSTI ID:5896118