3mgi | pdb_00003mgi

Ternary complex of a DNA polymerase lambda loop mutant

spinqualitylabelsall models 3mgi, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3mgi is a 4 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: D3T, MG, NA Related: 3mgh Gene: POLL (HUMAN) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [DPOLL_HUMAN] Repair polymerase. Involved in base excision repair (BER) responsible for repair of lesions that give rise to abasic (AP) sites in DNA. Has both DNA polymerase and terminal transferase activities. Has a 5'-deoxyribose-5-phosphate lyase (dRP lyase) activity. 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 PubMed Differences in the substrate specificity of mammalian family X DNA polymerases are proposed to partly depend on a loop (loop 1) upstream of the polymerase active site. To examine if this is the case in DNA polymerase lambda (pol lambda), here we characterize a variant of the human polymerase in which nine residues of loop 1 are replaced with four residues from the equivalent position in pol beta. Crystal structures of the mutant enzyme bound to gapped DNA with and without a correct dNTP reveal that the change in loop 1 does not affect the overall structure of the protein. Consistent with these structural data, the mutant enzyme has relatively normal catalytic efficiency for correct incorporation, and it efficiently participates in non-homologous end joining of double-strand DNA breaks. However, DNA junctions recovered from end-joining reactions are more diverse than normal, and the mutant enzyme is substantially less accurate than wild-type pol lambda in three different biochemical assays. Comparisons of the binary and ternary complex crystal structures of mutant and wild-type pol lambda suggest that loop 1 modulates pol lambda's fidelity by controlling dNTP-induced movements of the template strand and the primer-terminal 3'-OH as the enzyme transitions from an inactive to an active conformation. Loop 1 modulates the fidelity of DNA polymerase {lambda},Bebenek K, Garcia-Diaz M, Zhou RZ, Povirk LF, Kunkel TA Nucleic Acids Res. 2010 May 7. PMID:20435673 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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