Crystal structures of glycoside hydrolase family 136 lacto-N-biosidases from monkey gut- and human adult gut bacteria
Crystal structures of glycoside hydrolase family 136 lacto-N-biosidases from monkey gut- and human adult gut bacteria
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来自猴肠道和人类成人肠道细菌的糖苷水解酶家族 136 乳糖-N-二糖苷酶的晶体结构
DOI：
10.1093/bbb/zbac015
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Shinya Fushinobu
中科院分区：
文献类型：
--
作者：
Chihaya Yamada;Takane Katayama ;Shinya Fushinobu
糖苷水解酶家族136 （GH136）是在发现并分析婴儿肠道细菌长芽孢杆菌中乳酸- n -生物苷酶（LNBase）的基础上建立的。longumJCM1217 (BlLnbX)。bllnbx的同源基因广泛分布于人类肠道细菌和猴子双歧杆菌的基因组中。尽管在GH136家族中只报道了2种晶体结构。沙吉尼双歧杆菌、耐炎Tyzzerella和乳酸菌瘤胃球菌的细胞悬液显示LNBase活性。在大肠杆菌中对这3个物种的重组ln碱基及其特异性伴侣蛋白进行了功能表达，并测定了它们对硝基苯酚底物的动力学参数。碱基的晶体结构。saguiniandT。乳清素配合物与乳清- n -二糖I分别以2.51和1.92 Å的分辨率测定。这些结构保留了GH136和催化残基的β-螺旋折叠特征，但它们缺乏bllnbx中存在的金属离子。
Glycoside hydrolase family 136 (GH136) was established after the discovery and structural analysis of lacto-N-biosidase (LNBase) from the infant gut bacteriumBifidobacterium longumsubsp.longumJCM1217 (BlLnbX). Homologous genes ofBlLnbX are widely distributed in the genomes of human gut bacteria and monkeyBifidobacteriumspp., although only 2 crystal structures were reported in the GH136 family. Cell suspensions ofBifidobacterium saguini, Tyzzerella nexilis, andRuminococcus lactarisexhibited the LNBase activity. Recombinant LNBases of these 3 species were functionally expressed with their specific chaperones inEscherichia coli, and their kinetic parameters againstp-nitrophenol substrates were determined. The crystal structures of the LNBases fromB. saguiniandT. nexilisin complex with lacto-N-biose I were determined at 2.51 and 1.92 Å resolutions, respectively. These structures conserve a β-helix fold characteristic of GH136 and the catalytic residues, but they lack the metal ions that were present inBlLnbX.