Characterizing non-hydrolyzing Neisseria meningitidis serogroup A UDP-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase using UDP-N-acetylmannosamine (UDP-ManNAc) and derivatives.
Characterizing non-hydrolyzing Neisseria meningitidis serogroup A UDP-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase using UDP-N-acetylmannosamine (UDP-ManNAc) and derivatives.
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DOI：
10.1016/j.carres.2015.10.016
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发表时间：
2016-01
影响因子：
3.1
通讯作者：
Chen X
中科院分区：
文献类型：
--
作者：
Zhang L;Muthana MM;Yu H;McArthur JB;Qu J;Chen X
脑膜炎奈瑟菌血清群A非水解尿苷5′-二磷酸-N-乙酰葡萄糖胺（UDP-GlcNAc）2-差向异构酶（NmSacA）催化UDP-GlcNAc和尿苷5′-二磷酸-N-乙酰甘露糖胺（UDP-ManNAc）之间的相互转化。它是参与N. N.荚膜多糖[-6ManNAc 1-phosphate-]n生物合成的关键酶。脑膜炎血清群A是六个血清群（A、B、C、W-135、X和Y）之一，占大多数脑膜炎奈瑟氏菌病例。脑膜炎引起的细菌性败血症和脑膜炎。N. A群脑膜炎是发展中国家，特别是非洲大规模流行病的原因。在这里，我们报告说，UDP-ManNAc可以用作C-末端His 6标记的重组NmSacA（NmSacA-His 6）在UDP-GlcNAc的情况下的底物。NmSacA-His 6被UDP-GlcNAc激活，并被2-乙酰氨基葡萄糖醛和UDP抑制。底物特异性研究表明，NmSacA-His 6可以耐受多种化学酶促合成的UDP-ManNAc衍生物作为底物，尽管其活性远低于未修饰的UDP-ManNAc。同源建模和分子对接揭示了NmSacA底物特异性的可能结构决定因素。这是对N.脑膜炎血清群A UDP-GlcNAc 2-差向异构酶。
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.