3px0 | pdb_00003px0

Crystal Structure of Bacillus DNA Polymerase I Large Fragment Bound to DNA and dCTP-dA Mismatch (tautomer) in Closed Conformation

spinqualitylabelsall models 3px0, resolution 1.73Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3px0 is a 6 chain structure with sequence from "bacillus_kaustophilus"_prickett_1928 "bacillus kaustophilus" prickett 1928. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: DCP, MN, SO4 NonStd Res: DOC Related: 3pv8, 3px4, 3px6 Gene: polA, GK2730 ("Bacillus kaustophilus" Prickett 1928) Activity: DNA-directed DNA polymerase, with EC number 2.7.7.7 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Even though high-fidelity polymerases copy DNA with remarkable accuracy, some base-pair mismatches are incorporated at low frequency, leading to spontaneous mutagenesis. Using high-resolution X-ray crystallographic analysis of a DNA polymerase that catalyzes replication in crystals, we observe that a C*A mismatch can mimic the shape of cognate base pairs at the site of incorporation. This shape mimicry enables the mismatch to evade the error detection mechanisms of the polymerase, which would normally either prevent mismatch incorporation or promote its nucleolytic excision. Movement of a single proton on one of the mismatched bases alters the hydrogen-bonding pattern such that a base pair forms with an overall shape that is virtually indistinguishable from a canonical, Watson-Crick base pair in double-stranded DNA. These observations provide structural evidence for the rare tautomer hypothesis of spontaneous mutagenesis, a long-standing concept that has been difficult to demonstrate directly. Structural evidence for the rare tautomer hypothesis of spontaneous mutagenesis.,Wang W, Hellinga HW, Beese LS Proc Natl Acad Sci U S A. 2011 Oct 25;108(43):17644-8. Epub 2011 Oct 17. PMID:22006298 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also DNA polymerase 3D structures

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