Anaerobic regulation by an atypical Arc system in Shewanella oneidensis
Anaerobic regulation by an atypical Arc system in Shewanella oneidensis
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DOI：
10.1111/j.1365-2958.2005.04628.x
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发表时间：
2005-06-01
影响因子：
3.6
通讯作者：
Newman, DK
中科院分区：
文献类型：
--
作者：
Gralnick, JA;Brown, CT;Newman, DK
希瓦氏菌菌株MR-1以其呼吸多功能性而闻名，但对其如何调节参与无氧呼吸的基因知之甚少。在大肠杆菌中，Arc双组分系统在这一过程中起着重要作用，因此，我们确定了它在S. oneidensis。arcA从S. oneidensis与E. coliarcA突变体中的Arc调节子，而S. oneidensis构成了一套不同的基因。例如，大肠杆菌中最强的ArcA调控基因簇之一。coli，sdh不受S. oneidensis中的cyd位点，以及在E.在微氧条件下，在S. coli中被ArcA抑制。在厌氧条件下进行。我们发现在S. oneidensis含有预测编码二甲基亚砜（DMSO）还原酶亚基的基因。我们证明，这些基因编码一个功能性的DMSO还原酶，arcA突变体不能完全诱导其表达，是有缺陷的生长在DMSO厌氧条件下。而S. oneidensis缺乏高度保守的全长ArcB同源物，ArcA被与来自E. coli、HptA.这种蛋白单独不能弥补大肠杆菌中arcB的缺失。表明除了HptA之外，还需要另一种蛋白质来激活S. oneidensis。
Shewanella oneidensis strain MR-1 is well known for its respiratory versatility, yet little is understood about how it regulates genes involved in anaerobic respiration. The Arc two-component system plays an important role in this process in Escherichia coli; therefore, we determined its function in S. oneidensis. arcA from S. oneidensis complements an E. coli arcA mutant, but the Arc regulon in S. oneidensis constitutes a different suite of genes. For example, one of the strongest ArcA-regulated gene clusters in E. coli, sdh, is not regulated by the Arc system in S. oneidensis, and the cyd locus, which is induced by ArcA in E. coli under microaerobic conditions, is repressed by ArcA in S. oneidensis under anaerobic conditions. One locus that we identified as being potentially regulated by ArcA in S. oneidensis contains genes predicted to encode subunits of a dimethyl sulphoxide (DMSO) reductase. We demonstrate that these genes encode a functional DMSO reductase, and that an arcA mutant cannot fully induce their expression and is defective in growing on DMSO under anaerobic conditions. While S. oneidensis lacks a highly conserved full-length ArcB homologue, ArcA is partially activated by a small protein homologous to the histidine phosphotransfer domain of ArcB from E. coli, HptA. This protein alone is unable to compensate for the lack of arcB in E. coli, indicating that another protein is required in addition to HptA to activate ArcA in S. oneidensis.