Structure and conformational change of a replication protein A heterotrimer bound to ssDNA (original) (raw)

  1. Nikola P. Pavletich2,3
  2. 1Sloan-Kettering Division, Joan and Sanford I. Weill Graduate School of Medical Sciences, Cornell University, New York, New York 10065, USA;
  3. 2Howard Hughes Medical Institute, Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA

Abstract

Replication protein A (RPA) is the main eukaryotic ssDNA-binding protein with essential roles in DNA replication, recombination, and repair. RPA maintains the DNA as single-stranded and also interacts with other DNA-processing proteins, coordinating their assembly and disassembly on DNA. RPA binds to ssDNA in two conformational states with opposing affinities for DNA and proteins. The RPA–protein interactions are compatible with a low DNA affinity state that involves DNA-binding domain A (DBD-A) and DBD-B but not with the high DNA affinity state that additionally engages DBD-C and DBD-D. The structure of the high-affinity RPA–ssDNA complex reported here shows a compact quaternary structure held together by a four-way interface between DBD-B, DBD-C, the intervening linker (BC linker), and ssDNA. The BC linker binds into the DNA-binding groove of DBD-B, mimicking DNA. The associated conformational change and partial occlusion of the DBD-A–DBA-B protein–protein interaction site establish a mechanism for the allosteric coupling of RPA–DNA and RPA–protein interactions.

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