3nae
RB69 DNA Polymerase (Y567A) Ternary Complex with dATP Opposite GuanidinohydantoinRB69 DNA Polymerase (Y567A) Ternary Complex with dATP Opposite Guanidinohydantoin
Structural highlights
FunctionDPOL_BPR69 This polymerase possesses two enzymatic activities: DNA synthesis (polymerase) and an exonucleolytic activity that degrades single stranded DNA in the 3'- to 5'-direction. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedContinuous oxidative damage inflicted on DNA produces 7,8-dihydro-8-oxoguanine (8-oxoG), a commonly occurring lesion that can potentially cause cancer by producing G --> T transversions during DNA replication. Mild oxidation of 8-oxoG leads to the formation of hydantoins, specifically guanidinohydantoin (Gh) and spiroiminodihydantoin (Sp), which are 100% mutagenic because they encode almost exclusively the insertion of dAMP and dGMP (encoding G --> T and G --> C transversions, respectively). The wild-type (wt) pol alpha family DNA polymerase from bacteriophage RB69 (RB69pol) inserts dAMP and dGMP with low efficiency when situated opposite Gh. In contrast, the RB69pol Y567A mutant inserts both of these dNMPs opposite Gh with >100-fold higher efficiency than wt. We now report the crystal structure of the "closed" preinsertion complex for the Y567A mutant with dATP opposite a templating Gh (R-configuration) in a 13/18mer primer-template (P/T) at 2.0 A resolution. The structure data reveal that the Y to A substitution provides the nascent base pair binding pocket (NBP) with the flexibility to accommodate Gh by allowing G568 to move in the major-to-minor groove direction of the P/T. Thus, Gh is rejected as a templating base by wt RB69pol because G568 is inflexible, preventing Gh from pairing with the incoming dATP or dGTP base. Substitution of Ala for Tyr567 in RB69 DNA Polymerase Allows dAMP and dGMP To Be Inserted opposite Guanidinohydantoin .,Beckman J, Wang M, Blaha G, Wang J, Konigsberg WH Biochemistry. 2010 Sep 9. PMID:20795733[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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