Arginine171 of Chlamydomonas reinhardtii [Fe-Fe] hydrogenase HydA1 plays a crucial role in electron transfer to its catalytic center
Arginine171 of Chlamydomonas reinhardtii [Fe-Fe] hydrogenase HydA1 plays a crucial role in electron transfer to its catalytic center
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DOI：
10.1016/j.ijhydene.2012.12.078
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发表时间：
2013-03-07
影响因子：
7.2
通讯作者：
Bottin, Herve
中科院分区：
文献类型：
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作者：
Sybirna, Kateryna;Ezanno, Pierre;Bottin, Herve
[Fe-Fe]氢化酶的析氢活性比[Ni-Fe]氢化酶高3-4个数量级，仍然是用于产氢目的最有前途的酶类。对于莱茵衣藻 [Fe-Fe] 氢化酶 HydA1 来说，催化活性和电子传输问题至关重要。在这里，我们报告了莱茵衣藻 HydA1 的两种突变形式的特征。在甲基紫精依赖性产氢过程中，用天冬氨酸代替精氨酸 (171) 可使催化活性比野生型蛋白提高六倍。 171 位色氨酸不会导致甲基紫精诱导的活性发生任何变化。与此同时，这些突变导致铁氧还蛋白依赖性氢产生量大幅减少，而突变体形式的催化中心保持完整。该氨基酸（精氨酸（171））在 CrHydA1 H 簇环境中的定位表明该氢化酶催化活性的限制是由于电子转移到发生质子还原的催化中心的步骤。版权所有 (c) 2012，Hydrogen Energy Publications, LLC。由爱思唯尔有限公司出版。保留所有权利。
[Fe-Fe] hydrogenases, with hydrogen evolution activities outperforming [Ni-Fe] hydrogenases by 3-4 orders of magnitude, are still the most promising enzyme class for hydrogen production purposes. For Chlamydomonas reinhardtii [Fe-Fe] hydrogenase HydA1 the question of catalytic activity and electron transport is of main importance. Here we report the characterization of two mutant forms of C. reinhardtii HydA1. An aspartic acid in place of arginine(171) leads to a six-fold increase of the catalytic activity in comparison to the wild type protein during methyl viologen-dependent hydrogen production. Tryptophan in position 171 does not result in any change in methyl viologen-induced activity. At the same time these mutations lead to a strong decrease in ferredoxin-dependent hydrogen production while the catalytic center of mutant forms stays intact. The localization of this amino acid (arginine(171)) in the environment of CrHydA1 H-cluster indicates that the limitation of the catalytic activity of this hydrogenase is due to the electron transfer step to the catalytic center where the reduction of protons takes place. Copyright (c) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.