2kwv
Solution Structure of UBM1 of murine Polymerase iota in Complex with Ubiquitin
Structural highlights
FunctionPOLI_MOUSE Error-prone 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. Favors Hoogsteen base-pairing in the active site. Inserts the correct base with high-fidelity opposite an adenosine template. Exhibits low fidelity and efficiency opposite a thymidine template, where it will preferentially insert guanosine. May play a role in hypermutation of immunogobulin genes. Forms a Schiff base with 5'-deoxyribose phosphate at abasic sites, but may not have lyase activity (By similarity).[1] 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 PubMedUbiquitin-binding domains (UBDs) provide specificity to the ubiquitin system, which is also involved in translesion synthesis (TLS) in eukaryotic cells. Upon DNA damage, the UBDs (UBM domains) of polymerase iota (Pol iota) interact with ubiquitinated proliferating cell nuclear antigen to regulate the interchange between processive DNA polymerases and TLS. We report a biophysical analysis and solution structures of the two conserved UBM domains located in the C-terminal tail of murine Pol iota in complex with ubiquitin. The 35-amino acid core folds into a helix-turn-helix motif, which belongs to a novel domain fold. Similar to other UBDs, UBMs bind to ubiquitin on the hydrophobic surface delineated by Leu-8, Ile-44, and Val-70, however, slightly shifted toward the C terminus. In addition, UBMs also use electrostatic interactions to stabilize binding. NMR and fluorescence spectroscopy measurements revealed that UBMs bind monoubiquitin, and Lys-63- but not Lys-48-linked chains. Importantly, these biophysical data are supported by functional studies. Indeed, yeast cells expressing ubiquitin mutants specifically defective for UBM binding are viable but sensitive to DNA damaging conditions that require TLS for repair. Structural Analysis of the Conserved Ubiquitin-binding Motifs (UBMs) of the Translesion Polymerase iota in Complex with Ubiquitin.,Burschowsky D, Rudolf F, Rabut G, Herrmann T, Matthias P, Wider G J Biol Chem. 2011 Jan 14;286(2):1364-73. Epub 2010 Oct 6. PMID:20929865[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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