Mind the gap: diversity and reactivity relationships among multihaem cytochromes of the MtrA/DmsE family
Mind the gap: diversity and reactivity relationships among multihaem cytochromes of the MtrA/DmsE family
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DOI：
10.1042/bst20120106
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发表时间：
2012-12-01
影响因子：
3.9
通讯作者：
Elliott, Sean J.
中科院分区：
文献类型：
--
作者：
Bewley, Kathryn D.;Firer-Sherwood, Mackenzie A.;Elliott, Sean J.
希瓦氏菌MR-1在无氧呼吸过程中能够利用多种外部末端电子受体，如DMSO。促进这种电子转移的途径包括十血红素细胞色素DmsE，十血红素细胞色素的MtrA家族的一部分。尽管DmsE和MtrA都是涉及跨越类似于300埃（1埃=0.1 nm）宽的周质“间隙”的长程电子转移的十血红素细胞色素，但已显示MtrA的最大长度仅为105埃。在本文中，DmsE的进一步特征在于通过蛋白质膜伏安法，揭示了DmsE血红素辅因子的电化学显示宏观电位低于MtrA的100 mV。可能需要DmsE的氧化还原电位的这种调节来将电子穿梭到对DMSO还原特异的外膜蛋白。在S. oneidensis，如外膜蛋白MtrC，MtrF和OmcA，已被证明具有类似于MtrA的电化学性质，但具有不同的进化关系。
Shewanella oneidensis MR-1 has the ability to use many external terminal electron acceptors during anaerobic respiration, such as DMSO. The pathway that facilitates this electron transfer includes the decahaem cytochrome DmsE, a paralogue of the MtrA family of decahaem cytochromes. Although both DmsE and MtrA are decahaem cytochromes implicated in the long-range electron transfer across a similar to 300 angstrom (1 angstrom=0.1 nm) wide periplasmic 'gap', MtrA has been shown to be only 105 angstrom in maximal length. In the present paper, DmsE is further characterized via protein film voltammetry, revealing that the electrochemistry of the DmsE haem cofactors display macroscopic potentials lower than those of MtrA by 100 mV. It is possible this tuning of the redox potential of DmsE is required to shuttle electrons to the outer-membrane proteins specific to DMSO reduction. Other decahaem cytochromes found in S. oneidensis, such as the outer-membrane proteins MtrC, MtrF and OmcA, have been shown to have electrochemical properties similar to those of MtrA, yet possess a different evolutionary relationship.