中文摘要：研究对源于不同细菌家族的氧化还原酶Prxs进行了综合的系统进化分析，着重分析了肺炎支原体Prxs的进化历史，并验证了该家族缺失可溶性半胱氨酸Cys(R)的假说。同时，对拥有1个、2个或缺失催化半胱氨酸的肺炎支原体Prxs的功能分别进行了突变分析。当移除MhPrx 过氧化半胱氨酸Cys(P)后会导致MhPrx功能完全失活，这进一步证实了过氧化半胱氨酸Cys(P)的催化功能；加入与2-半胱氨酸同源体相对应的第二个半胱氨酸即可溶性半胱氨酸Cys(R)，即构成推断的MhPrx前体结构，则兼有其酶的活性。总而言之，本研究结果表明，MhPrx是最新从2-半胱氨酸 Prx前体物分离出来的，研究为膜体纲及其他细菌家族Prx结构、功能和进化提供了基础。
 
外文摘要：The minimal genome of the mollicute Mycoplasma hyopneumoniae, the etiological agent of porcine enzootic pneumonia, encodes a limited repertoire of antioxidant enzymes that include a single and atypical peroxiredoxin (MhPrx), whose evolution and function were studied here. MhPrx has only one catalytic cysteine, in contrast with some of its possible ancestors (2-Cys peroxiredoxins), which have two. Although it is more similar to 2-Cys orthologs, MhPrx can still function with a single peroxidatic cysteine (Cys(P)), using non-thiolic electron donors to reduce it. Therefore, MhPrx could be a representative of a possible group of 2-Cys peroxiredoxins, which have lost the resolving cysteine (Cys(R)) residue without losing their catalytic properties. To further investigate MhPrx evolution, we performed a comprehensive phylogenetic analysis in the context of several bacterial families, including Prxs belonging to Tpx and AhpE families, shedding light on the evolutionary history of Mycoplasmataceae Prxs and giving support to the hypothesis of a relatively recent loss of the Cys(R) within this family. Moreover, mutational analyses provided insights into MhPrx function with one, two, or without catalytic cysteines. While removal of the MhPrx putative Cys(P) caused complete activity loss, confirming its catalytic role, the introduction of a second cysteine in a site correspondent to that of the Cys(R) of a 2-Cys orthologue, as in the MhPrx supposed ancestral form, was compatible with enzyme activity. Overall, our phylogenetic and mutational studies support that MhPrx recently diverged from a 2-Cys Prx ancestor and pave the way for future studies addressing structural, functional, and evolutive aspects of peroxiredoxin subfamilies in Mollicutes and other bacteria.
外文关键词：Mycoplasma; Peroxiredoxin; Tpx; AhpE; Molecular evolution
作者：Gonchoroski, T; Virginio, VG; Thompson, CE; Paes, JA; Machado, CX; Ferreira, HB
作者单位：巴西南大河联邦大学
期刊名称：MOLECULAR GENETICS AND GENOMICS
期刊影响因子：2.622
出版年份：2017
出版刊次：4
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