期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 107, 期 42, 页码 18138-18142出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1010318107
关键词
Acetobacterium; anaerobic respiration; electron transport; Na+ pump; Rnf
资金
- Deutsche Forschungsgemeinschaft
The anaerobic acetogenic bacterium Acetobacterium woodii carries out a unique type of Na+-motive, anaerobic respiration with caffeate as electron acceptor, termed caffeate respiration. Central, and so far the only identified membrane-bound reaction in this respiration pathway, is a ferredoxin: NAD(+) oxidoreductase (Fno) activity. Here we show that inverted membrane vesicles of A. woodii couple electron transfer from reduced ferredoxin to NAD(+) with the transport of Na+ from the outside into the lumen of the vesicles. Na+ transport was electrogenic, and accumulation was inhibited by sodium ionophores but not protonophores, demonstrating a direct coupling of Fno activity to Na+ transport. Results from inhibitor studies are consistent with the hypothesis that Fno activity coupled to Na+ translocation is catalyzed by the Rnf complex, a membrane-bound, iron-sulfur and flavin-containing electron transport complex encoded by many bacterial and some archaeal genomes. Fno is a unique type of primary Na+ pump and represents an early evolutionary mechanism of energy conservation that expands the redox range known to support life. In addition, it explains the lifestyle of many anaerobic bacteria and gives a mechanistic explanation for the enigma of the energetic driving force for the endergonic reduction of ferredoxin with NADH plus H+ as reductant in a number of aerobic bacteria.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据