Crystal structure of glycoside hydrolase family 31 α-xylosidase from a soil metagenome
Crystal structure of glycoside hydrolase family 31 α-xylosidase from a soil metagenome
复制标题
土壤宏基因组中糖苷水解酶家族 31 α-木糖苷酶的晶体结构
DOI：
10.1093/bbb/zbac058
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Yaoi Katsuro
中科院分区：
文献类型：
--
作者：
Nakamichi Yusuke;Matsuzawa Tomohiko;Watanabe Masahiro;Yaoi Katsuro
MeXyl 31是从土壤宏基因组文库中分离到的α-木糖苷酶，属于糖苷水解酶家族31（GH 31）。该酶降解α-木糖基底物，如异苦味酸糖、α-d-吡喃木糖基-（1→6）-吡喃葡萄糖。MeXyl 31的晶体结构在1.80 nm分辨率下测定。MeXyl 31形成四聚体状态。在−1亚位点（α-木糖结合位点）与木糖的复合结构表明该酶严格识别α-木糖。MeXyl 31与其同源物尼日尔α-木糖苷酶GH 31之间的结构比较提供了对MeXyl 31的阳性亚位点的见解。首先，在四聚体酶中，两个单体（催化单体和相邻单体）参与底物识别。第二，相邻单体构成MeXyl 31中的一部分正亚位点。对接模拟和定点突变表明，Arg 100从相邻的单体是部分参与识别的吡喃葡萄糖的异苦楝糖。
MeXyl31, a member of glycoside hydrolase family 31 (GH31), is the α-xylosidase isolated from a soil metagenomic library. The enzyme degrades α-xylosyl substrate such as isoprimeverose, α-d-xylopyranosyl-(1→6)-glucopyranose. The crystal structure of MeXyl31 was determined at 1.80 Å resolution. MeXyl31 forms the tetrameric state. The complexed structure with a xylose in the −1 subsite (α-xylose binding site) shows that the enzyme strictly recognizes α-xylose. Structural comparison between MeXyl31 and its homologue,Aspergillus nigerα-xylosidase in GH31, gave insights into the positive subsite of MeXyl31. First, in the tetrameric enzyme, two monomers (a catalytic monomer and the adjacent monomer), are involved in substrate recognition. Second, the adjacent monomer composes a part of positive subsites in MeXyl31. Docking simulation and site-directed mutagenesis suggested that the Arg100 from the adjacent monomer is partially involved in the recognizing of a glucopyranose of isoprimeverose.