同源重组修复是重要的DNA修复途径之一，Holliday junction (HJ)的迁移和处理是其后期的重要过程。细菌中HJ迁移和解离由RuvABC复合体共同完成，其中RuvA和RuvB为ATP酶和DNA移位酶，而RuvC为HJ特异性的核酸内切酶（称为HJ解离酶）。古菌和真核生物中的解离酶已相继被发现，但RuvAB结构类似物均未鉴定出来。我们的前期分析发现, 硫化叶菌中的HJ解离酶Hjc与一新型且保守的 ATP酶(命名为PINA)互作, 二蛋白编码基因在基因组中位于同一位点且相互重叠，暗示PINA可能参与HJ的加工，类似RuvAB。本研究将分析该新型ATP酶的生化性质包括ATP酶水解、DNA结合与解旋和HJ迁移等活性及其与Hjc的相互作用，解析PINA晶体结构，用遗传方法分析PINA在细胞内的重要性及作用，对该新型而保守的ATP酶进行功能定位，加深对古菌DNA重组修复机制的认识和理解。

DNA recombinational repair is one of the most important DNA repair pathways. Holliday junction (HJ) migration and processing are important late stage steps of this pathway. In bacteria, RuvABC complex functions in HJ migration and cleavage, in which RuvA and RuvB are ATPases and DNA translocases, while RuvC is a HJ-specific endonuclease. Resolvases from archaea and eukarya have been characterized recently, however the structural homolog of RuvAB have not been identified. Our preliminary studies revealed that the archaeal HJ resolvase Hjc interacted with a novel conserved ATPase named PINA in Sulfolobus. Genes encoding the two proteins are adjacent with short overlaps, indicating PINA may function in HJ processing as HJ migration as RuvAB. In his study, the biochemical properties of PINA, including ATPase, DNA binding and unwinding, HJ migration activities and the interaction between PINA and Hjc will be analyzed. The crystal structures of PINA will solved and the in vivo role of the protein will be investigated. It is expected that the study will clariy the function of the novel conserved ATPase in archaea and deepen our understanding of DNA recombinational repair in archaea.