Backbone Dynamics and Model-Free Analysis of N-terminal Domain of Human Replication Protein A 70

Abstract

Replication protein A (RPA) is an essential single-stranded DNA binding protein in DNA processing. It is known that N terminal domain of RPA70 (RPA70N) recruits various protein partners including damage-response proteins such as p53, ATRIP, Rad9, and MRE11. Although the common binding residues of RPA70N were revealed, dynamic properties of the protein are not studied yet. In this study, we measured 15N relaxation parameters (T1, T2 and heteronuclear NOE) of human RPA70N and analyzed them using model-free analysis. Our data showed that the two loops near the binding site experience fast time scale motion while the binding site do not. It suggests that the protein binding surface of RPA70N is mostly rigid for minimizing entropy cost of binding and the loops can experience conformational changes.