The process of homologous recombination is heavily dependent on the RecA family of recombinases for repair of DNA double-strand breaks. These recombinases are responsible for identifying homologies and forming heteroduplex DNA between substrate ssDNA and dsDNA templates, activities that are modified by various accessory factors. In this work we describe the biochemical functions of the SsoRal2 recombinase paralog from the crenarchaeon Sulfolobus solfataricus. We found that the SsoRal2 protein is a DNA-independent ATPase that, unlike the other S. solfataricus paralogs, does not bind either ss- or dsDNA. Instead, SsoRal2 alters the ssDNA binding activity of the SsoRadA recombinase in conjunction with another paralog, SsoRal1. In the presence of SsoRal1, SsoRal2 has a modest effect on strand invasion but effectively abrogates strand exchange activity. Taken together, these results indicate that SsoRal2 assists in nucleoprotein filament modulation and control of strand exchange in S. solfataricus.

中文翻译：

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展现新的抗重组酶活性的古细菌重组酶旁系同源物的表征。

同源重组的过程在很大程度上依赖于RecA家族的重组酶来修复DNA双链断裂。这些重组酶负责鉴定同源性，并在底物ssDNA和dsDNA模板之间形成异源双链DNA，这些活性被各种辅助因子修饰。在这项工作中，我们描述了来自crenarchaeon Sulfolobus solfataricus的SsoRal2重组酶旁系同源物的生化功能。我们发现，SsoRal2蛋白是一种不依赖DNA的ATPase，与其他solfataricus旁系同源蛋白不同，它不结合ss-或dsDNA。相反，SsoRal2与另一个旁系同源物SsoRal1一起改变了SsoRadA重组酶的ssDNA结合活性。在存在SsoRal1的情况下，SsoRal2对链入侵的影响不大，但有效地消除了链交换活性。