Energy conservation via organohalide respiration in Sulfurospirillum multivorans

在厌氧菌多源硫螺旋藻中，地下水污染物四氯乙烯（PCE）的还原脱氯作用通过电子传递磷酸化（有机卤化物呼吸）与ATP的形成相耦合。关键酶是还原性PCE脱卤酶（PceA），一种质周含铁硫蛋白。本项目旨在i)阐明PceA的电子转移途径，并鉴定和表征氢化酶或甲酸脱氢酶与还原脱卤酶之间的电子传导组分（可溶性或膜结合），ii)揭示PceA的假定膜锚PceB的作用，iii)揭示酶的催化机制。为了实现这些目标，将使用差异蛋白质组学研究和蛋白质-蛋白质相互作用分析来识别呼吸链成分。倒置囊泡的研究将用于鉴定有机卤化物呼吸的可溶性电子供体。多vorans硫螺旋藻基因组的明确突变和随后对细胞（或酶）变异的光谱研究将允许深入探索电子流向还原脱卤酶（或酶内）。该项目获得的数据将提供有关微生物节能与还原脱氯基本原理的重要信息。

In the anaerobe Sulfurospirillum multivorans the reductive dechlorination of the groundwater contaminant tetrachloroethene (PCE) is coupled to the formation of ATP via electron transport phosphorylation (organohalide respiration). The key enzyme is the reductive PCE dehalogenase (PceA), a periplasmic corrinoid-containing iron-sulfur protein. This project is aimed i) to elucidate the electron-transfer pathway to PceA and to identify and characterize the electron-conducting components (soluble or membrane-bound) between the hydrogenase or formate dehydrogenase and the reductive dehalogenase, ii) to reveal the role of PceB, the putative membrane anchor of PceA, and iii) to unravel the catalytic mechanism of the enzyme. To achieve these aims, differential proteomic studies and protein-protein interaction analyses will be used to identify the respiratory chain components. Studies with inverted vesicles will be performed to identify soluble electron donors for organohalide respiration. Defined mutagenesis of the Sulfurospirillum multivorans genome and subsequent spectroscopic investigations of the cell (or enzyme) variants will allow an in-depth exploration of the electron flow to the reductive dehalogenase (or within the enzyme). The data obtained in this project will provide crucial information about the fundamentals of microbial energy conservation coupled to reductive dechlorination.