title: Characterizing non-hydrolyzing Neisseria meningitidis serogroup A UDP-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase using UDP-N-acetylmannosamine (UDP-ManNAc) and derivatives.
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.
authors.affiliation: Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Musleh M
authors.initials: MM
authors.lastname: Muthana
authors.affiliation: Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Hai
authors.initials: H
authors.lastname: Yu
authors.affiliation: Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: John B
authors.initials: JB
authors.lastname: McArthur
authors.affiliation: Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Jingyao
authors.initials: J
authors.lastname: Qu
authors.affiliation: Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA. Electronic address: xiichen@ucdavis.edu.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D002238:Carbohydrate Epimerases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020134:Catalytic Domain; D003001:Cloning, Molecular; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D006595:Hexosamines / Q000378:metabolism / Q000494:pharmacology; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity; D014530:Uridine Diphosphate / Q000378:metabolism / Q000494:pharmacology; D014537:Uridine Diphosphate N-Acetylglucosamine / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D006595:Hexosamines; C019231:2-acetamidoglucal; D014537:Uridine Diphosphate N-Acetylglucosamine; D014530:Uridine Diphosphate; D002238:Carbohydrate Epimerases; C100033:UDP acetylglucosamine-2-epimerase
keywords: Epimerization; Neisseria meningitidis; UDP-GlcNAc; UDP-GlcNAc 2-epimerase; UDP-ManNAc