Structural Analysis of Replication Protein A Recruitment of the DNA Damage Response Protein SMARCAL1.Feldkamp, M.D., Mason, A.C., Eichman, B.F., Chazin, W.J.
(2014) Biochemistry 53: 3052-3061
- PubMed: 24730652
- DOI: 10.1021/bi500252w
- PubMed Abstract:
SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A-like1 (SMARCAL1) is a recently identified DNA damage response protein involved in remodeling stalled replication forks. The eukaryotic single-strand DNA binding p ...
SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A-like1 (SMARCAL1) is a recently identified DNA damage response protein involved in remodeling stalled replication forks. The eukaryotic single-strand DNA binding protein replication protein A (RPA) recruits SMARCAL1 to stalled forks in vivo and facilitates regression of forks containing leading strand gaps. Both activities are mediated by a direct interaction between an RPA binding motif (RBM) at the N-terminus of SMARCAL1 and the C-terminal winged-helix domain of the RPA 32 kDa subunit (RPA32C). Here we report a biophysical and structural characterization of the SMARCAL1-RPA interaction. Isothermal titration calorimetry and circular dichroism spectroscopy revealed that RPA32C binds SMARCAL1-RBM with a Kd of 2.5 μM and induces a disorder-to-helix transition. The crystal structure of RPA32C was refined to 1.4 Å resolution, and the SMARCAL1-RBM binding site was mapped on the structure on the basis of nuclear magnetic resonance chemical shift perturbations. Conservation of the interaction surface to other RBM-containing proteins allowed construction of a model for the RPA32C/SMARCAL1-RBM complex. The implications of our results are discussed with respect to the recruitment of SMARCAL1 and other DNA damage response and repair proteins to stalled replication forks.
Department of Biochemistry, ‡Department of Biological Sciences, §Department of Chemistry, and ∥Center for Structural Biology, Vanderbilt University , Nashville, Tennessee 37232, United States.