2lsj | pdb_00002lsj
Solution structure of the mouse Rev1 CTD in complex with the Rev1-interacting Region (RIR)of Pol Kappa
Structural highlights
Function[REV1_MOUSE] Deoxycytidyl transferase involved in DNA repair. Transfers a dCMP residue from dCTP to the 3'-end of a DNA primer in a template-dependent reaction. May assist in the first step in the bypass of abasic lesions by the insertion of a nucleotide opposite the lesion. Required for normal induction of mutations by physical and chemical agents.[1] [POLK_MOUSE] DNA polymerase specifically involved in DNA repair. Plays an important role in translesion synthesis, where the normal high-fidelity DNA polymerases cannot proceed and DNA synthesis stalls. Depending on the context, it inserts the correct base, but causes frequent base transitions, transversions and frameshifts. Lacks 3'-5' proofreading exonuclease activity. Forms a Schiff base with 5'-deoxyribose phosphate at abasic sites, but does not have lyase activity (By similarity).[2] Publication Abstract from PubMedTranslesion synthesis is a fundamental biological process that enables DNA replication across lesion sites to ensure timely duplication of genetic information at the cost of replication fidelity, and it is implicated in development of cancer drug resistance after chemotherapy. The eukaryotic Y-family polymerase Rev1 is an essential scaffolding protein in translesion synthesis. Its C-terminal domain (CTD), which interacts with translesion polymerase zeta through the Rev7 subunit and with polymerases kappa, iota, and eta in vertebrates through the Rev1-interacting region (RIR), is absolutely required for function. We report the first solution structures of the mouse Rev1 CTD and its complex with the Pol kappa RIR, revealing an atypical four-helix bundle. Using yeast two-hybrid assays, we have identified a Rev7-binding surface centered at the alpha2-alpha3 loop and N-terminal half of alpha3 of the Rev1 CTD. Binding of the mouse Pol kappa RIR to the Rev1 CTD induces folding of the disordered RIR peptide into a three-turn alpha-helix, with the helix stabilized by an N-terminal cap. RIR binding also induces folding of a disordered N-terminal loop of the Rev1 CTD into a beta-hairpin that projects over the shallow alpha1-alpha2 surface and creates a deep hydrophobic cavity to interact with the essential FF residues juxtaposed on the same side of the RIR helix. Our combined structural and biochemical studies reveal two distinct surfaces of the Rev1 CTD that separately mediate the assembly of extension and insertion translesion polymerase complexes and provide a molecular framework for developing novel cancer therapeutics to inhibit translesion synthesis. Multifaceted recognition of vertebrate Rev1 by translesion polymerases zeta and kappa.,Wojtaszek J, Liu J, D'Souza S, Wang S, Xue Y, Walker GC, Zhou P J Biol Chem. 2012 Jul 27;287(31):26400-8. doi: 10.1074/jbc.M112.380998. Epub 2012, Jun 14. PMID:22700975[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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