Grein Fabian, Ramos Ana Raquel, Venceslau Sofia S, Pereira Inês A C
Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Oeiras, Portugal.
Biochim Biophys Acta. 2013 Feb;1827(2):145-60. doi: 10.1016/j.bbabio.2012.09.001. Epub 2012 Sep 11.
Behind the versatile nature of prokaryotic energy metabolism is a set of redox proteins having a highly modular character. It has become increasingly recognized that a limited number of redox modules or building blocks appear grouped in different arrangements, giving rise to different proteins and functionalities. This modularity most likely reveals a common and ancient origin for these redox modules, and is obviously reflected in similar energy conservation mechanisms. The dissimilation of sulfur compounds was probably one of the earliest biological strategies used by primitive organisms to obtain energy. Here, we review some of the redox proteins involved in dissimilatory sulfur metabolism, focusing on sulfate reducing organisms, and highlight links between these proteins and others involved in different processes of anaerobic respiration. Noteworthy are links to the complex iron-sulfur molybdoenzyme family, and heterodisulfide reductases of methanogenic archaea. We discuss how chemiosmotic and electron bifurcation/confurcation may be involved in energy conservation during sulfate reduction, and how introduction of an additional module, multiheme cytochromes c, opens an alternative bioenergetic strategy that seems to increase metabolic versatility. Finally, we highlight new families of heterodisulfide reductase-related proteins from non-methanogenic organisms, which indicate a widespread distribution for these protein modules and may indicate a more general involvement of thiol/disulfide conversions in energy metabolism. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems.
原核生物能量代谢的多功能性背后是一组具有高度模块化特征的氧化还原蛋白。人们越来越认识到，有限数量的氧化还原模块或构建块以不同的排列方式聚集在一起，产生了不同的蛋白质和功能。这种模块化很可能揭示了这些氧化还原模块的共同古老起源，并且明显体现在相似的能量守恒机制中。硫化合物的异化作用可能是原始生物最早用于获取能量的生物学策略之一。在这里，我们综述了一些参与异化硫代谢的氧化还原蛋白，重点是硫酸盐还原生物，并强调了这些蛋白与参与厌氧呼吸不同过程的其他蛋白之间的联系。值得注意的是与复杂铁硫钼酶家族以及产甲烷古菌的异二硫还原酶的联系。我们讨论了化学渗透和电子分叉/汇合在硫酸盐还原过程中如何参与能量守恒，以及引入额外的模块——多血红素细胞色素c——如何开启一种似乎增加代谢多功能性的替代生物能量策略。最后，我们强调了来自非产甲烷生物的异二硫还原酶相关蛋白的新家族，这表明这些蛋白模块分布广泛，可能表明硫醇/二硫键转换在能量代谢中更普遍地参与。本文是名为：生物能量系统的进化方面的特刊的一部分。
