Structural insights on the catalytic site protection of human carbonyl reductase 1 by glutathione
Structural insights on the catalytic site protection of human carbonyl reductase 1 by glutathione
复制标题
谷胱甘肽保护人羰基还原酶 1 催化位点的结构见解
DOI：
10.1016/j.jsb.2015.09.005
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发表时间：
2015-10-01
影响因子：
3
通讯作者：
Ding, Yu
中科院分区：
文献类型：
--
作者：
Liang, Qingnan;Liu, Rui;Ding, Yu
nadph依赖性的人羰基还原酶I （hCBR1）是短链脱氢酶/还原酶蛋白家族的成员，在普遍存在的内源性和外源性含羰基化合物的代谢中起着重要作用。谷胱甘肽（GSH）也是hCBR1的辅助因子，但其在酶的羰基还原酶功能中的作用尚不清楚。在这项研究中，我们展示了在没有底物或抑制剂的情况下，hCBR1与GSH复合物的晶体结构。有趣的是，我们发现当底物与hCBR1结合时，GSH分子呈现的构型与先前报道的完全不同。我们的结构表明GSH有助于hCBR1的底物选择性，并通过类似开关的机制保护hCBR1的催化中心。等温滴定量热和酶学数据表明，在无底物存在的情况下，GSH直接与hCBR1结合。酶学数据也显示谷胱甘肽保护NADPH免受氧化小分子的攻击。这是首次发现谷胱甘肽具有辅酶的功能。我们的晶体结构成功地为hCBR1的底物选择性和hCBR1与GSH之间的相互作用提供了关键的见解。(C) 2015爱思唯尔公司版权所有。
The NADPH-dependent human carbonyl reductase I (hCBR1), a member of the short-chain dehydrogenase/reductase protein family, plays an important role in the ubiquitous metabolism of endogenous and xenobiotic carbonyl containing compounds. Glutathione (GSH) is also a cofactor of hCBR1, however, its role in the carbonyl reductase function of the enzyme is still unclear. In this study, we presented the crystal structure of hCBR1 in complex with GSH, in the absence of its substrates or inhibitors. Interestingly, we found that the GSH molecule presents in a configuration quite different from that was previously reported when substrate is binding to hCBR1. Our structure indicates that GSH contributes to the substrate selectivity of hCBR1 and protects the catalytic center of hCBR1 through a switch-like mechanism. The isothermal titration calorimetry and enzymology data shows that GSH directly binding with hCBR1 when there's no substrate exist. The enzymology data also shows GSH protects NADPH being attacked by oxidative small molecules. This is the first time that GSH is found to demonstrate such functions as a co-enzyme. Our crystal structure succeeds in providing critical insights into the substrate selectivity of hCBR1 and the interaction between hCBR1 and GSH. (C) 2015 Elsevier Inc. All rights reserved.