Analyses of the large subunit histidine-rich motif expose an alternative proton transfer pathway in [NiFe] hydrogenases.
Analyses of the large subunit histidine-rich motif expose an alternative proton transfer pathway in [NiFe] hydrogenases.
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DOI：
10.1371/journal.pone.0034666
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Kovács KL
中科院分区：
文献类型：
--
作者：
Szőri-Dorogházi E;Maróti G;Szőri M;Nyilasi A;Rákhely G;Kovács KL
在[NiFe]氢化酶大亚基中发现了一个功能未知的高度保守的富含组氨酸的区域。HxHxxHxxHxH序列出现在大多数膜结合氢化酶中，但这些组氨酸中只有两个存在于细胞质中。对T. roseopersicina膜附着Hyn氢化酶公开了仅通过His104残基的置换显著影响酶活性。计算分析的氢键网络中的大亚基表明，第二个组氨酸的这个基序可能是一个质子转移途径，包括Arg487，Asp103，His104和Glu436的组件。假定的转移途径的保守氨基酸的取代损害了Hyn氢化酶的活性。Western杂交表明突变体氢化酶的细胞水平与野生型相似。大多数基于理论建模，很少有质子转移途径已经建议[NiFe]氢化酶。我们的研究结果提出了一种替代路线的[NiFe]活性中心和蛋白质表面之间的质子转移。这个模型的一个新的特点是，这个质子通路位于大亚基相对于小亚基的位置的相对侧。这是第一个研究提出了一个系统的分析，在硅片预测质子易位途径[镍铁]氢化酶的定点诱变。
A highly conserved histidine-rich region with unknown function was recognized in the large subunit of [NiFe] hydrogenases. The HxHxxHxxHxH sequence occurs in most membrane-bound hydrogenases, but only two of these histidines are present in the cytoplasmic ones. Site-directed mutagenesis of the His-rich region of the T. roseopersicina membrane-attached Hyn hydrogenase disclosed that the enzyme activity was significantly affected only by the replacement of the His104 residue. Computational analysis of the hydrogen bond network in the large subunits indicated that the second histidine of this motif might be a component of a proton transfer pathway including Arg487, Asp103, His104 and Glu436. Substitutions of the conserved amino acids of the presumed transfer route impaired the activity of the Hyn hydrogenase. Western hybridization was applied to demonstrate that the cellular level of the mutant hydrogenases was similar to that of the wild type. Mostly based on theoretical modeling, few proton transfer pathways have already been suggested for [NiFe] hydrogenases. Our results propose an alternative route for proton transfer between the [NiFe] active center and the surface of the protein. A novel feature of this model is that this proton pathway is located on the opposite side of the large subunit relative to the position of the small subunit. This is the first study presenting a systematic analysis of an in silico predicted proton translocation pathway in [NiFe] hydrogenases by site-directed mutagenesis.
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影响因子：
3.2
作者：
Burgdorf, T;De Lacey, AL;Friedrich, B
通讯作者：
Friedrich, B
DOI：
10.1016/s0969-2126(99)80072-0
发表时间：
1999-05-01
期刊：
STRUCTURE WITH FOLDING & DESIGN
影响因子：
--
作者：
Garcin, E;Vernede, X;Fontecilla-Camps, JC
通讯作者：
Fontecilla-Camps, JC
DOI：
10.1073/pnas.0803689105
发表时间：
2008-08-12
影响因子：
11.1
作者：
Leroux, Fanny;Dementin, Sebastien;Leger, Christophe
通讯作者：
Leger, Christophe
影响因子：
2.9
作者：
Henderson, LM
通讯作者：
Henderson, LM
影响因子：
2.1
作者：
KOVACS, KL;BAGYINKA, C
通讯作者：
BAGYINKA, C