GDP-4-keto-6-deoxy-D-mannose差向异构酶/还原酶大肠杆菌,生物合成的关键酶GDP-L-fucose,显示红色的同源蛋白质总科的结构特点。
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Rizzi M, Tonetti M, Vigevani P,二L, Bisso,植物广告,波尔多D, Bolognesi M
GDP-4-keto-6-deoxy-D-mannose差向异构酶/还原酶大肠杆菌,生物合成的关键酶GDP-L-fucose,显示红色的同源蛋白质总科的结构特点。
结构。1998年11月15日,6 (11):1453 - 65。
- PubMed ID
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9817848 (在PubMed]
- 文摘
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背景:鸟苷5 '磷酸氢盐的过程L-fucose (GDP-L-fucose)从原核生物在进化过程中生物合成是守恒的。在动物中,GDP-L-fucose fucosyltransferases的底物参与生物合成和装修glycoconjugates,包括ABH血型和Lewis-system抗原。新创的GDP-L-fucose生物合成的途径GDP-D-mannose包括GDP-D-mannose 4、6脱水酶(GMD)和GDP-4-keto-6-deoxy-D-mannose差向异构酶/还原酶(通用)。的催化机制和两种酶的三维结构已经被阐明。严重缺乏白细胞粘附(小伙子)II型遗传综合征是由于在这个新创通路缺陷。结果:“分离”的晶体结构和holo-GMER已经确定分辨率2.1和2.2,分别。homodimeric每个亚基(2 x 34 kDa)酶是由两个域组成的。six-stranded罗斯曼褶皱n端结构域,结合辅酶ii +;c端域(约100残留物)显示一个α/β拓扑。辅酶ii +与残留Arg12和Arg36腺甙磷酸核糖; moreover, a protein loop based on the Gly-X-X-Gly-X-X-Gly motif (where X is any amino acid) stabilizes binding of the coenzyme diphosphate bridge. The nicotinamide and the connected ribose ring are located close to residues Ser107, Tyr136 and Lys140, the putative GMER active-site center. CONCLUSIONS: The GMER fold is reminiscent of that observed for UDP-galactose epimerase (UGE) from Escherichia coli. Consideration of the enzyme fold and of its main structural features allows assignment of GMER to the reductase-epimerase-dehydrogenase (RED) enzyme homology superfamily, to which short-chain dehydrogenase/reductases (SDRs) also belong. The location of the NADP+ nicotinamide ring at an interdomain cleft is compatible with substrate binding in the C-terminal domain.