Bochkarev A, Pfuetzner R A, Edwards A M, Frappier L
Institute for Molecular Biology and Biotechnology, Cancer Research Group, McMaster University, Hamilton, Ontario, Canada.
Nature. 1997 Jan 9;385(6612):176-81. doi: 10.1038/385176a0.
The single-stranded-DNA-binding proteins (SSBs) are essential for DNA function in prokaryotic and eukaryotic cells, mitochondria, phages and viruses. The structures of four SSBs have been solved, but the molecular details of the interaction of SSBs with DNA remain speculative. We report here the crystal structure at 2.4 A resolution of the single-stranded-DNA-binding domain of human replication protein A (RPA) bound to DNA. Replication protein A is a heterotrimeric SSB that is highly conserved in eukaryotes. The largest subunit, RPA70, binds to single-stranded (ss)DNA and mediates interactions with many cellular and viral proteins. The DNA-binding domain, which lies in the middle of RPA70, comprises two structurally homologous subdomains oriented in tandem. The ssDNA lies in a channel that extends from one subdomain to the other. The structure of each RPA70 subdomain is similar to those of the bacteriophage SSBs, indicating that the mechanism of ssDNA-binding is conserved.
单链DNA结合蛋白（SSB）对于原核和真核细胞、线粒体、噬菌体及病毒中的DNA功能至关重要。四种SSB的结构已得到解析，但SSB与DNA相互作用的分子细节仍属推测。我们在此报告了与DNA结合的人复制蛋白A（RPA）单链DNA结合结构域分辨率为2.4埃的晶体结构。复制蛋白A是一种在真核生物中高度保守的异源三聚体SSB。最大的亚基RPA70与单链（ss）DNA结合，并介导与许多细胞和病毒蛋白的相互作用。位于RPA70中间的DNA结合结构域由两个串联排列的结构同源亚结构域组成。ssDNA位于从一个亚结构域延伸到另一个亚结构域的通道中。每个RPA70亚结构域的结构与噬菌体SSB的结构相似，表明ssDNA结合机制是保守的。
