Structural analyses and yeast production of the β-1,3-1,4-glucanase catalytic module encoded by the licB gene of Clostridium thermocellum
Structural analyses and yeast production of the β-1,3-1,4-glucanase catalytic module encoded by the licB gene of Clostridium thermocellum
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DOI：
10.1016/j.enzmictec.2015.01.002
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发表时间：
2015-04-01
影响因子：
3.4
通讯作者：
Guo, Rey-Ting
中科院分区：
文献类型：
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作者：
Chen, Chun-Chi;Huang, Jian-Wen;Guo, Rey-Ting
热纤梭菌（Clostridium thermocellum，CtLic 16 A）的嗜热糖苷水解酶家族16（GH 16）β-1，3-1，4-葡聚糖酶具有较高的比活和优异的热稳定性，在工业应用中具有巨大的潜力。为了了解其分子机制，CtLic 16 A的晶体结构被确定为1.95埃分辨率。该酶折叠成经典的GH 16 β-β-卷曲结构，该结构由两个相互重叠的β-折叠组成，底物结合裂缝位于内部β-折叠的凹侧。两个Bis-Tris丙烷分子被发现在积极和消极的底物结合位点。结构分析表明，CtLic 16 A和其他GH 16 β-1，3-1，4-葡聚糖酶结构之间的主要差异发生在蛋白质外部。此外，CtLic 16 A的高催化效率和热特性在巴斯德毕赤酵母中产生的酶中得以保留，从而鼓励其进一步的商业应用。(C)2015 Elsevier Inc. All rights reserved.
A thermophilic glycoside hydrolase family 16 (GH16)beta-1,3-1,4-glucanase from Clostridium thermocellum (CtLic16A) holds great potentials in industrial applications due to its high specific activity and outstanding thermostability. In order to understand its molecular machinery, the crystal structure of CtLic16A was determined to 1.95 angstrom resolution. The enzyme folds into a classic GH16 beta-jellyroll architecture which consists of two beta-sheets atop each other, with the substrate-binding cleft lying on the concave side of the inner beta-sheet. Two Bis-Tris propane molecules were found in the positive and negative substrate binding sites. Structural analysis suggests that the major differences between the CtLic16A and other GH16 beta-1,3-1,4-glucanase structures occur at the protein exterior. Furthermore, the high catalytic efficacy and thermal profile of the CtLic16A are preserved in the enzyme produced in Pichia pastoris, encouraging its further commercial applications. (C) 2015 Elsevier Inc. All rights reserved.