1fgu
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SSDNA-BINDING DOMAIN OF THE LARGE SUBUNIT OF REPLICATION PROTEIN A
OverviewOverview
Although structures of single-stranded (ss)DNA-binding proteins (SSBs), have been reported with and without ssDNA, the mechanism of ssDNA binding, in eukarya remains speculative. Here we report a 2.5 Angstroms structure, of the ssDNA-binding domain of human replication protein A (RPA), (eukaryotic SSB), for which we previously reported a structure in complex, with ssDNA. A comparison of free and bound forms of RPA revealed that, ssDNA binding is associated with a major reorientation between, and, significant conformational changes within, the structural, modules--OB-folds--which comprise the DNA-binding domain. Two OB-folds, whose tandem orientation was stabilized by the presence of DNA, adopted, multiple orientations in its absence. Within the OB-folds, extended loops, implicated in DNA binding significantly changed conformation in the, absence of DNA. Analysis of intermolecular contacts suggested the, possibility that other RPA molecules and/or other proteins could compete, with DNA for the same binding site. Using this mechanism, protein-protein, interactions can regulate, and/or be regulated by DNA binding. Combined, with available biochemical data, this structure also suggested a dynamic, model for the DNA-binding mechanism.
About this StructureAbout this Structure
1FGU is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Structure of the major single-stranded DNA-binding domain of replication protein A suggests a dynamic mechanism for DNA binding., Bochkareva E, Belegu V, Korolev S, Bochkarev A, EMBO J. 2001 Feb 1;20(3):612-8. PMID:11157767
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