7ktb | pdb_00007ktb
DNA Polymerase Mu, 8-oxodGTP:Ct Reaction State Ternary Complex, 10 mM Mn2+ (40min)
Structural highlights
FunctionDPOLM_HUMAN Gap-filling polymerase involved in repair of DNA double-strand breaks by non-homologous end joining (NHEJ). Participates in immunoglobulin (Ig) light chain gene rearrangement in V(D)J recombination.[1] [2] [3] [4] Publication Abstract from PubMedOxidized dGTP (8-oxo-7,8-dihydro-2 -deoxyguanosine triphosphate, 8-oxodGTP) insertion by DNA polymerases strongly promotes cancer and human disease. How DNA polymerases discriminate against oxidized and undamaged nucleotides, especially in error-prone double strand break (DSB) repair, is poorly understood. High-resolution time-lapse X-ray crystallography snapshots of DSB repair polymerase mu undergoing DNA synthesis reveal that a third active site metal promotes insertion of oxidized and undamaged dGTP in the canonical anti-conformation opposite template cytosine. The product metal bridged O8 with product oxygens, and was not observed in the syn-conformation opposite template adenine (A(t)). Rotation of A(t) into the syn-conformation enabled undamaged dGTP misinsertion. Exploiting metal and substrate dynamics in a rigid active site allows 8-oxodGTP to circumvent polymerase fidelity safeguards to promote pro-mutagenic double strand break repair. Watching a double strand break repair polymerase insert a pro-mutagenic oxidized nucleotide.,Jamsen JA, Sassa A, Shock DD, Beard WA, Wilson SH Nat Commun. 2021 Apr 6;12(1):2059. doi: 10.1038/s41467-021-21354-6. PMID:33824325[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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