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首页> 外文期刊>Acta crystallographica.Section D. Biological crystallography >1.8 and 1.9 A resolution structures of the Penicillium amagasakiense and Aspergillus niger glucose oxidases as a basis for modelling substrate complexes.
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1.8 and 1.9 A resolution structures of the Penicillium amagasakiense and Aspergillus niger glucose oxidases as a basis for modelling substrate complexes.

机译：1.8和1.9的解析结构青霉菌amagasakiense和黑曲霉葡萄糖氧化酶类作为造型的基础底物复合物。

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摘要

Glucose oxidase is a flavin-dependent enzyme which catalyses the oxidation of beta-D-glucose by molecular oxygen to delta-gluconolactone and hydrogen peroxide. The structure of the enzyme from Aspergillus niger, previously refined at 2.3 A resolution, has been refined at 1.9 A resolution to an R value of 19.0%, and the structure of the enzyme from Penicillium amagasakiense, which has 65% sequence identity, has been determined by molecular replacement and refined at 1.8 A resolution to an R value of 16.4%. The structures of the partially deglycosylated enzymes have an r.m.s. deviation of 0.7 A for main-chain atoms and show four N-glycosylation sites, with an extended carbohydrate moiety at Asn89. Substrate complexes of the enzyme from A. niger were modelled by force-field methods. The resulting model is consistent with results from site-directed mutagenesis experiments and shows the beta-D-glucose molecule in the active site of glucose oxidase, stabilized by 12 hydrogen bonds and by hydrophobic contacts to three neighbouring aromatic residues and to flavin adenine dinucleotide. Other hexoses, such as alpha-D-glucose, mannose and galactose, which are poor substrates for the enzyme, and 2-deoxy-D-glucose, form either fewer bonds or unfavourable contacts with neighbouring amino acids. Simulation of the complex between the reduced enzyme and the product, delta-gluconolactone, has provided an explanation for the lack of product inhibition by the lactone.
机译：葡萄糖氧化酶是一种flavin-dependent酶beta-D-glucose氧化的催化作用分子氧delta-gluconolactone和过氧化氢。从黑曲霉,以前精制为2.3一项决议,已被提炼为1.9 A分辨率的R值19.0%,从特异酶的结构amagasakiense, 65%序列的身份,已经由分子置换和精制决议的R值1.816.4%。deglycosylated酶r.m.s.偏差0.7的主链原子和显示四个N-glycosylation网站,扩展碳水化合物在Asn89一半。答:尼日尔的酶被模仿力场的方法。与定点的结果一致诱变实验,显示了beta-D-glucose分子的活性部位葡萄糖氧化酶,由12个氢键稳定和疏水接触三个邻国芳香残留物和黄素腺嘌呤二核苷酸。alpha-D-glucose、甘露糖和半乳糖可怜的酶的底物,2-deoxy-D-glucose,更少的债券或形式不利的联系邻近的氨基酸酸。减少酶和产品,delta-gluconolactone,提供了一个解释产物抑制的缺乏内酯。

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