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Crystal structure of full-length human RPA14/32 heterodimer
Structural highlights
FunctionRFA2_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] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedReplication protein A (RPA) is the ubiquitous, eukaryotic single-stranded DNA (ssDNA) binding protein and is essential for DNA replication, recombination, and repair. Here, crystal structures of the soluble RPA heterodimer, composed of the RPA14 and RPA32 subunits, have been determined for the full-length protein in multiple crystal forms. In all crystals, the electron density for the N-terminal (residues 1-42) and C-terminal (residues 175-270) regions of RPA32 is weak and of poor quality indicating that these regions are disordered and/or assume multiple positions in the crystals. Hence, the RPA32 N terminus, that is hyperphosphorylated in a cell-cycle-dependent manner and in response to DNA damaging agents, appears to be inherently disordered in the unphosphorylated state. The C-terminal, winged helix-loop-helix, protein-protein interaction domain adopts several conformations perhaps to facilitate its interaction with various proteins. Although the ordered regions of RPA14/32 resemble the previously solved protease-resistant core crystal structure, the quaternary structures between the heterodimers are quite different. Thus, the four-helix bundle quaternary assembly noted in the original core structure is unlikely to be related to the quaternary structure of the intact heterotrimer. An organic ligand binding site between subunits RPA14 and RPA32 was identified to bind dioxane. Comparison of the ssDNA binding surfaces of RPA70 with RPA14/32 showed that the lower affinity of RPA14/32 can be attributed to a shallower binding crevice with reduced positive electrostatic charge. Structure of the full-length human RPA14/32 complex gives insights into the mechanism of DNA binding and complex formation.,Deng X, Habel JE, Kabaleeswaran V, Snell EH, Wold MS, Borgstahl GE J Mol Biol. 2007 Dec 7;374(4):865-76. Epub 2007 Oct 2. PMID:17976647[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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