DNA序列和核苷酸辅因子对hRad51与单链DNA结合的影响：hRad52在募集过程中的作用。

Effect of DNA sequence and nucleotide cofactors on hRad51 binding to ssDNA: role of hRad52 in recruitment.

作者信息

Navadgi Vasundhara M, Shukla Ashish, Rao Basuthkar J

机构信息

Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India.

出版信息

Biochem Biophys Res Commun. 2005 Aug 26;334(2):696-701. doi: 10.1016/j.bbrc.2005.06.145.

DOI:10.1016/j.bbrc.2005.06.145

PMID:16018971

Abstract

hRad51 binding to ssDNA is significantly lowered in the presence of a nucleotide cofactor ATP/ADP/ATPgammaS. In these conditions, presence of trace amounts of hRad52 protein restores hRad51 binding to DNA. In the absence of any nucleotide cofactor where intrinsic binding of hRad51 to ssDNA is higher, hRad52 brings about no improved binding. hRad51 binding to ssDNA is strongly influenced by the DNA sequence. The protein binding to repeat sequences is poor compared to that of mixed DNA sequence. Interestingly, presence of hRad52 restores the ability of hRad51 binding to such DNA targets as well. Moreover, all the cooperative effects of hRad52 on hRad51 binding are highly specific to the latter's binding to ssDNA and not to dsDNA. These results help us to model important mechanistic steps of hRad51 presynapsis on ssDNA templates.

摘要

在核苷酸辅因子ATP/ADP/ATPγS存在的情况下，hRad51与单链DNA（ssDNA）的结合显著降低。在这些条件下，痕量hRad52蛋白的存在可恢复hRad51与DNA的结合。在不存在任何核苷酸辅因子的情况下，hRad51与ssDNA的内在结合较高，此时hRad52不会改善结合情况。hRad51与ssDNA的结合受到DNA序列的强烈影响。与混合DNA序列相比，该蛋白与重复序列的结合较差。有趣的是，hRad52的存在也能恢复hRad51与此类DNA靶点的结合能力。此外，hRad52对hRad51结合的所有协同作用都高度特异性地针对后者与ssDNA的结合，而非双链DNA（dsDNA）。这些结果有助于我们构建hRad51在ssDNA模板上突触前重要机制步骤的模型。