1. Characterizing non-hydrolyzing Neisseria meningitidis serogroup A UDP-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase using UDP-N-acetylmannosamine (UDP-ManNAc) and derivatives.
- Author
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Zhang, Lei, Muthana, Musleh M, Yu, Hai, McArthur, John B, Qu, Jingyao, and Chen, Xi
- Subjects
Neisseria meningitidis ,Carbohydrate Epimerases ,Hexosamines ,Uridine Diphosphate N-Acetylglucosamine ,Uridine Diphosphate ,Enzyme Inhibitors ,Cloning ,Molecular ,Enzyme Activation ,Amino Acid Sequence ,Catalytic Domain ,Substrate Specificity ,Molecular Sequence Data ,Molecular Docking Simulation ,Epimerization ,UDP-GlcNAc ,UDP-GlcNAc 2-epimerase ,UDP-ManNAc ,Rare Diseases ,2.2 Factors relating to the physical environment ,Aetiology ,Infection ,Medicinal and Biomolecular Chemistry ,Organic Chemistry ,Biochemistry and Cell Biology - Abstract
Neisseria meningitidis serogroup A non-hydrolyzing uridine 5'-diphosphate-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase (NmSacA) catalyzes the interconversion between UDP-GlcNAc and uridine 5'-diphosphate-N-acetylmannosamine (UDP-ManNAc). It is a key enzyme involved in the biosynthesis of the capsular polysaccharide [-6ManNAcα1-phosphate-]n of N. meningitidis serogroup A, one of the six serogroups (A, B, C, W-135, X, and Y) that account for most cases of N. meningitidis-caused bacterial septicemia and meningitis. N. meningitidis serogroup A is responsible for large epidemics in the developing world, especially in Africa. Here we report that UDP-ManNAc could be used as a substrate for C-terminal His6-tagged recombinant NmSacA (NmSacA-His6) in the absence of UDP-GlcNAc. NmSacA-His6 was activated by UDP-GlcNAc and inhibited by 2-acetamidoglucal and UDP. Substrate specificity study showed that NmSacA-His6 could tolerate several chemoenzymatically synthesized UDP-ManNAc derivatives as substrates although its activity was much lower than non-modified UDP-ManNAc. Homology modeling and molecular docking revealed likely structural determinants of NmSacA substrate specificity. This is the first detailed study of N. meningitidis serogroup A UDP-GlcNAc 2-epimerase.
- Published
- 2016