RPA2_DBD_D: A subfamily of OB folds corresponding to the OB fold of the central ssDNA-binding domain (DBD)-D of human RPA2 (also called RPA32). RPA2 is a subunit of Replication protein A (RPA). RPA is a nuclear ssDNA-binding protein (SSB) which appears to be involved in all aspects of DNA metabolism including replication, recombination, and repair. RPA also mediates specific interactions of various nuclear proteins. In animals, plants, and fungi, RPA is a heterotrimer with subunits of 70KDa (RPA1), 32kDa (RPA2), and 14 KDa (RPA3). The major DNA binding activity of RPA is associated with RPA1 DBD-A and DBD-B; RPA2 DBD-D is a weak ssDNA-binding domain. RPA2 DBD-D is also involved in trimerization. The ssDNA binding mechanism is believed to be multistep and to involve conformational change. N-terminal to human RPA2 DBD-D is a domain containing all the known phosphorylation sites of RPA. Human RPA2 is phosphorylated in a cell cycle dependent manner in response to DNA damage. RPA2 interacts physically with menin; the gene encoding menin is a tumor suppressor gene disrupted in multiple endocrine neoplasia type I. This subfamily also includes RPA2 from Cryptosporidium parvum (CpRPA2). CpRPA2 is an SSB, which can be phosphorylated by DNA-PK in vitro.
Structure:1L1O_DEF; Human RPA trimerization core interface; defined at 3.5A contacts between subunits in the hetrotrimer. - View structure with Cn3D
Comment:The RPA trimerization core consists of DBD-D (the central DNA-binding domain of RPA2), DBD-C (the C-terminal DNA-binding domain of RPA1), and intact RPA3. Each contains an OB-fold domain flanked by a helix at the C-terminus, which mediate trimerization.
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