Subdivision of the Bacterioferritin Comigratory Protein Family of Bacterial Peroxiredoxins Based on Catalytic Activity
Subdivision of the Bacterioferritin Comigratory Protein Family of Bacterial Peroxiredoxins Based on Catalytic Activity
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DOI：
10.1021/bi901703m
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发表时间：
2010-02-16
期刊：
影响因子：
2.9
通讯作者：
Brown, Alan R.
中科院分区：
文献类型：
--
作者：
Clarke, David J.;Ortega, Ximena P.;Brown, Alan R.
过氧化物酶是普遍存在的蛋白质，其催化氢过氧化物的还原，从而赋予对氧化应激的抗性。利用高分辨质谱，我们最近重新分类了一个这样的过氧化物氧还蛋白，细菌铁蛋白共迁移蛋白（BCP）的大肠杆菌，作为一个非典型的2-Cys过氧化物氧还蛋白，通过形成分子内的二硫键之间的活性和解决半胱氨酸的功能。一个工程化的E.大肠杆菌BCP，缺乏解析半胱氨酸，通过一种新的催化途径保持酶的活性。与活性半胱氨酸不同，BCP过氧化物酶的解析半胱氨酸在家族的所有成员中并不保守。为了阐明缺乏解析半胱氨酸的天然BCP酶的催化机制，我们研究了新洋葱伯克霍尔德氏菌的BCP同源物。我们证明了B.新洋葱BCP（BcBCP）同源物通过1-Cys催化途径起作用。在催化过程中，BcBCP可以利用硫氧还蛋白作为次磺酸中间体的还原剂。然而，利用谷胱甘肽作为解析半胱氨酸和谷氧还蛋白作为氧化还原配偶体观察到显著更高的过氧化物酶活性。在BcBCP中引入一个解析半胱氨酸，将活性从1-Cys途径改变为非典型的2-Cys途径，类似于E.大肠杆菌酶。与本地B相反。在新洋葱酶中，硫氧还蛋白是这种非典型2-Cys变体的优选氧化还原配偶体。BCP缺陷型B。cenocepacia表现出生长阶段依赖性的氧化杀伤超敏反应。在序列比对的基础上，我们认为本文所述的BcBCP代表了细菌BCP过氧化物酶的主要类别。据我们所知，这是对其催化活性的首次详细表征。这些研究支持BCP家族的过氧化物酶分为两类的基础油的催化活性。
Peroxiredoxins are ubiquitous proteins that catalyze the reduction of hydroperoxides, thus conferring resistance to oxidative stress. Using high-resolution mass spectrometry, We recently reclassified one Such peroxiredoxin, bacterioferritin comigratory protein (BCP) of Escherichia coli, as an atypical 2-Cys peroxiredoxin that functions through the formation of an intramolecular disulfide bond between the active and resolving cysteine. An engineered E. coli BCP, which lacked the resolving cysteine, retained enzyme activity through a novel catalytic pathway. Unlike the active cysteine, the resolving cysteine of BCP peroxiredoxins is not conserved across all members of the family. To clarify the catalytic mechanism of native BCP enzymes that lack the resolving cysteine, we have investigated the BCP homologue of Burkholderia cenocepacia. We demonstrate that the B. cenocepacia BCP (BcBCP) homologue functions through a 1-Cys catalytic pathway. During catalysis, BcBCP can utilize thioredoxin as a reductant for the sulfenic acid intermediate. However, significantly higher peroxidase activity is observed utilizing glutathione as a resolving cysteine and glutaredoxin as a redox partner. Introduction of a resolving cysteine into BcBCP changes the activity from 1-Cys pathway to an atypical 2-Cys pathway, analogous to the E. coli enzyme. In contrast to the native B. cenocepacia enzyme, thioredoxin is the preferred redox partner for this atypical 2-Cys variant. BCP-deficient B. cenocepacia exhibit a growth-phase-dependent hypersensitivity to oxidative killing. Oil the basis of sequence alignments, we believe that BcBCP described herein is representative of the major class of bacterial BCP peroxiredoxins. To Our knowledge, this is the first detailed characterization of their catalytic activity. These Studies Support the subdivision of the BCP Family of peroxiredoxins into two classes based oil their catalytic activity.