Characterization of site-specific mutants of alkylhydroperoxide reductase with dual functionality from Helicobacter pylori.
Characterization of site-specific mutants of alkylhydroperoxide reductase with dual functionality from Helicobacter pylori.
复制标题
幽门螺杆菌具有双重功能的烷基氢过氧化物还原酶位点特异性突变体的表征。
DOI：
10.1093/jb/mvp209
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发表时间：
2010
影响因子：
2.7
通讯作者：
S. Chiou
中科院分区：
文献类型：
--
作者：
Chun;M. Chuang;Yuan;W. Chuang;Pei;S. Chiou
烷基过氧化氢还原酶（Alkylhydroperoxide reductase，AhpC）是幽门螺杆菌（Helicobacter pylori，HP）中一种重要的抗氧化蛋白。通过序列比对和结构比较，发现HP-AhpC与人过氧化物酶（peroxiredoxins，hPrx）的同源性高于其它真细菌AhpC蛋白。与hPrxI类似，天然HP-AhpC作为单个亚基的二聚体存在，包括具有低表面疏水性的α-螺旋和β-折叠结构域。AhpC在氧化应激下可形成700至高于2，000 kDa的高分子量（HMW）聚集体，在硫氧还蛋白（Trx）存在下具有分子伴侣活性。过氧化物还原酶活性的进一步分析表明，HP-AhpC比hPrxI对H2 O2的抗性更强。然而，H2 O2对HP-AhpC和hPrxI的失活机制似乎相似，这一点通过天然凝胶电泳以及随后的双向凝胶电泳（2-DE）和LC-MS/MS的蛋白质组学鉴定得到证实。与具有伴侣活性的T90 D-hPrxI突变体相比，位点特异性突变体T87 D-HP-AhpC不形成HMW伴侣复合物。这两种进化上遥远但功能上相关的酶的比较可能揭示具有相似蛋白质结构的HP-AhpC和hPrxI中双重功能的进化和发展的机制。
Alkylhydroperoxide reductase (AhpC) is an abundant and important antioxidant protein present in Helicobacter pylori (HP), a spiral Gram-negative microaerophilic bacterium. By sequence alignment and structure comparison, HP-AhpC was found to be more homologous to human peroxiredoxins (hPrx) than to other eubacterial AhpC proteins. Similar to hPrxI, native HP-AhpC existed as a dimer of single subunit, comprising alpha-helix and beta-sheet domains with low surface hydrophobicity. AhpC can form high-molecular-weight (HMW) aggregates ranging from 700 to higher than 2,000 kDa under oxidative stress, possessing chaperone activity in the presence of thioredoxin (Trx). Further analysis of peroxide-reductase activities showed that HP-AhpC was more resistant to H(2)O(2) than hPrxI. However, the mechanism of enzyme inactivation to H(2)O(2) appeared to be similar for both HP-AhpC and hPrxI as revealed by native gel electrophoresis followed by proteomic identification using two-dimensional gel electrophoresis (2-DE) and LC-MS/MS. In contrast to T90D-hPrxI mutant with chaperone activity, site-specific mutant T87D-HP-AhpC did not form HMW chaperone complexes. The comparison of these two evolutionarily distant and yet functionally related enzymes may shed some light on the mechanism(s) underlying the evolution and development of the dual functionality in HP-AhpC and hPrxI with similar protein structure.
AhpF 的两个工程异二聚体之一（来自鼠伤寒沙门氏菌的 NADH：过氧化还原酶氧化还原酶）的活性揭示了结构域之间的亚基内电子转移。
影响因子：
2.9
作者：
Reynolds,CM;Poole,LB
通讯作者：
Poole,LB
影响因子：
3.9
作者：
Koshkin, A;Knudsen, GM;de Montellano, PRO
通讯作者：
de Montellano, PRO