3bq1
Insertion ternary complex of Dbh DNA polymerase
Structural highlights
FunctionDPO4_SULAC Poorly processive, error-prone DNA polymerase involved in untargeted mutagenesis. Copies undamaged DNA at stalled replication forks, which arise in vivo from mismatched or misaligned primer ends. These misaligned primers can be extended by PolIV. Exhibits no 3'-5' exonuclease (proofreading) activity. May be involved in translesional synthesis (By similarity). 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 PubMedDbh is a Y family translesion DNA polymerase that accurately bypasses some damaged forms of deoxyguanosine, but also generates single-base deletion errors at frequencies of up to 50%, in specific hot spot sequences. We describe preinsertion binary, insertion ternary, and postinsertion binary crystal structures of Dbh synthesizing DNA after making a single-base deletion. The skipped template base adopts an extrahelical conformation stabilized by interactions with the C-terminal domain of the enzyme. DNA translocation and positioning of the next templating base at the active site, with space opposite to accommodate incoming nucleotide, occur independently of nucleotide binding, incorporation, and pyrophosphate release. We also show that Dbh creates single-base deletions more rapidly when the skipped base is located two or three bases upstream of the nascent base pair than when it is directly adjacent to the templating base, indicating that Dbh predominantly creates single-base deletions by template slippage rather than by dNTP-stabilized misalignment. Structural insights into the generation of single-base deletions by the Y family DNA polymerase dbh.,Wilson RC, Pata JD Mol Cell. 2008 Mar 28;29(6):767-79. PMID:18374650[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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