View source for 3kd5


==Closed ternary complex of an RB69 gp43 fingers domain mutant complexed with an acyclic GMP terminated primer template pair and phosphonoformic acid.==
<StructureSection load='3kd5' size='340' side='right'caption='[[3kd5]], [[Resolution|resolution]] 2.69&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3kd5]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_phage_RB69 Escherichia phage RB69]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3KD5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3KD5 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.69&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=4DG:2-[(2-AMINO-6-OXO-1,6-DIHYDRO-9H-PURIN-9-YL)METHOXY]ETHYL+DIHYDROGEN+PHOSPHATE'>4DG</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=PPF:PHOSPHONOFORMIC+ACID'>PPF</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3kd5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3kd5 OCA], [https://pdbe.org/3kd5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3kd5 RCSB], [https://www.ebi.ac.uk/pdbsum/3kd5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3kd5 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/DPOL_BPR69 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.
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== Publication Abstract from PubMed ==
Phosphonoformic acid (PFA, foscarnet) belongs to a class of antiviral drugs that inhibit the human cytomegalovirus DNA polymerase (UL54) by mimicking the pyrophosphate leaving group of the nucleotide transfer reaction. Difficulties expressing UL54 have hampered investigation of the precise structural requirements rendering inhibition by this drug. However, a previously engineered chimeric DNA polymerase, constructed by mutating the homologous polymerase from bacteriophage RB69 (gp43) to express several variable elements from UL54, can bypass this obstacle because of its favorable expression and acquired sensitivity to PFA (Tchesnokov, E. P., Obikhod, A., Schinazi, R. F., and Gotte, M. (2008) J. Biol. Chem. 283, 34218-34228). Here, we compare two crystal structures that depict the chimeric DNA polymerase with and without PFA bound. PFA is visualized for the first time in the active site of a DNA polymerase, where interactions are resolved between the PP(i) mimic and two basic residues absolutely conserved in the fingers domain of family B polymerases. PFA also chelates metal ion B, the cation that contacts the triphosphate tail of the incoming nucleotide. These DNA complexes utilize a primer-template pair enzymatically chain-terminated by incorporation of acyclo-GMP, the phosphorylated form of the anti-herpes drug acyclovir. We postulate that the V478W mutation present in the chimera is critical in that it pushes the fingers domain to more readily adopt the closed conformation whether or not the drug is bound. The closed state of the fingers domain traps the variant polymerase in the untranslocated state and increases affinity for PFA. This finding provides a model for the mechanism of UL54 stalling by PFA.

Phosphonoformic acid inhibits viral replication by trapping the closed form of the DNA polymerase.,Zahn KE, Tchesnokov EP, Gotte M, Doublie S J Biol Chem. 2011 Jul 15;286(28):25246-55. doi: 10.1074/jbc.M111.248864. Epub, 2011 May 12. PMID:21566148<ref>PMID:21566148</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 3kd5" style="background-color:#fffaf0;"></div>

==See Also==
*[[DNA polymerase 3D structures|DNA polymerase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Escherichia phage RB69]]
[[Category: Large Structures]]
[[Category: Doublie S]]
[[Category: Zahn KE]]