4ou0
From Proteopedia
Crystal Structure of RPA32C
Structural highlights
Function[RFA2_HUMAN] Required for DNA recombination, repair and replication. The activity of RP-A is mediated by single-stranded DNA binding and protein interactions. Required for the efficient recruitment of the DNA double-strand break repair factor RAD51 to chromatin in response to DNA damage.[1] [2] [3] [4] Functions as component of the alternative replication protein A complex (aRPA). aRPA binds single-stranded DNA and probably plays a role in DNA repair; it does not support chromosomal DNA replication and cell cycle progression through S-phase. In vitro, aRPA cannot promote efficient priming by DNA polymerase alpha but supports DNA polymerase delta synthesis in the presence of PCNA and replication factor C (RFC), the dual incision/excision reaction of nucleotide excision repair and RAD51-dependent strand exchange.[5] [6] [7] [8] Publication Abstract from PubMedSWI/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 (ss) 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 CD spectroscopy revealed that RPA32C binds the SMARCAL1-RBM with a Kd of 3 muM and induces a disorder-to-helix transition. The crystal structure of RPA32C was refined to 1.4 A resolution and the SMARCAL1-RBM binding site was mapped on the structure on the basis of NMR chemical shift perturbations. Conservation of the interaction surface to other RBM-containing proteins enabled 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. Structural analysis of RPA recruitment of the DNA damage response protein SMARCAL1.,Feldkamp MD, Mason AC, Eichman BF, Chazin WJ Biochemistry. 2014 Apr 15. PMID:24730652[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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