4e3s | pdb_00004e3s

RB69 DNA Polymerase Ternary Complex with dQTP Opposite dT

spinqualitylabelsall models 4e3s, resolution 2.04Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4e3s is a 3 chain structure with sequence from Escherichia phage RB69. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CA, DOC, QTP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [DPOL_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. Publication Abstract from PubMed Minor groove hydrogen bonding (HB) interactions between DNA polymerases (pols) and N3 of purines or O2 of pyrimidines have been proposed to be essential for DNA synthesis from results obtained using various nucleoside analogues lacking the N3 or O2 contacts that interfered with primer extension. Because there has been no direct structural evidence to support this proposal, we decided to evaluate the contribution of minor groove HB interactions with family B pols. We have used RB69 DNA pol and 3-deaza-2'-deoxyadenosine (3DA), an analogue of 2-deoxyadenosine, which has the same HB pattern opposite T but with N3 replaced with a carbon atom. We then determined pre-steady-state kinetic parameters for the insertion of dAMP opposite dT using primer/templates (P/T)-containing 3DA. We also determined three structures of ternary complexes with 3DA at various positions in the duplex DNA substrate. We found that the incorporation efficiency of dAMP opposite dT decreased 10(2)-10(3)-fold even when only one minor groove HB interaction was missing. Our structures show that the HB pattern and base pair geometry of 3DA/dT is exactly the same as those of dA/dT, which makes 3DA an optimal analogue for probing minor groove HB interactions between a DNA polymerase and a nucleobase. In addition, our structures provide a rationale for the observed 10(2)-10(3)-fold decrease in the rate of nucleotide incorporation. The minor groove HB interactions between position n - 2 of the primer strand and RB69pol fix the rotomer conformations of the K706 and D621 side chains, as well as the position of metal ion A and its coordinating ligands, so that they are in the optinal orientation for DNA synthesis. Probing Minor Groove Hydrogen Bonding Interactions between RB69 DNA Polymerase and DNA.,Xia S, Christian TD, Wang J, Konigsberg WH Biochemistry. 2012 May 17. PMID:22571765 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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