9ics: Difference between revisions
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|PDB= 9ics |SIZE=350|CAPTION= <scene name='initialview01'>9ics</scene>, resolution 2.900Å | |PDB= 9ics |SIZE=350|CAPTION= <scene name='initialview01'>9ics</scene>, resolution 2.900Å | ||
|SITE= | |SITE= | ||
|LIGAND= <scene name='pdbligand= | |LIGAND= <scene name='pdbligand=DA:2'-DEOXYADENOSINE-5'-MONOPHOSPHATE'>DA</scene>, <scene name='pdbligand=DC:2'-DEOXYCYTIDINE-5'-MONOPHOSPHATE'>DC</scene>, <scene name='pdbligand=DCT:2',3'-DIDEOXYCYTIDINE+5'-TRIPHOSPHATE'>DCT</scene>, <scene name='pdbligand=DG:2'-DEOXYGUANOSINE-5'-MONOPHOSPHATE'>DG</scene>, <scene name='pdbligand=DT:THYMIDINE-5'-MONOPHOSPHATE'>DT</scene>, <scene name='pdbligand=MN:MANGANESE+(II)+ION'>MN</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene> | ||
|ACTIVITY= | |ACTIVITY= | ||
|GENE= | |GENE= | ||
|DOMAIN= | |||
|RELATEDENTRY= | |||
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=9ics FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9ics OCA], [http://www.ebi.ac.uk/pdbsum/9ics PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=9ics RCSB]</span> | |||
}} | }} | ||
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[[Category: Pelletier, H.]] | [[Category: Pelletier, H.]] | ||
[[Category: Sawaya, M R.]] | [[Category: Sawaya, M R.]] | ||
[[Category: complex (nucleotidyltransferase/dna)]] | [[Category: complex (nucleotidyltransferase/dna)]] | ||
[[Category: dna repair]] | [[Category: dna repair]] | ||
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[[Category: nucleotidyltransferase]] | [[Category: nucleotidyltransferase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 05:46:19 2008'' | ||
Revision as of 05:46, 31 March 2008
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| , resolution 2.900Å | |||||||
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| Ligands: | , , , , , , | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
DNA POLYMERASE BETA (E.C.2.7.7.7)/DNA COMPLEX + 2',3'-DIDEOXYCYTIDINE-5'-TRIPHOSPHATE, SOAKED IN THE PRESENCE OF DDCTP AND MNCL2
OverviewOverview
When crystals of human DNA polymerase beta (pol beta) complexed with DNA [Pelletier, H., Sawaya, M. R., Wolfle, W., Wilson, S. H., & Kraut, J. (1996) Biochemistry 35, 12742-12761] are soaked in the presence of dATP and Mn2+, X-ray structural analysis shows that nucleotidyl transfer to the primer 3'-OH takes place directly in the crystals, even though the DNA is blunt-ended at the active site. Under similar crystal-soaking conditions, there is no evidence for a reaction when Mn2+ is replaced by Mg2+, which is thought to be the divalent metal ion utilized by most polymerases in vivo. These results suggest that one way Mn2+ may manifest its mutagenic effect on polymerases is by promoting greater reactivity than Mg2+ at the catalytic site, thereby allowing the nucleotidyl transfer reaction to take place with little or no regard to instructions from a template. Non-template-directed nucleotidyl transfer is also observed when pol beta-DNA cocrystals are soaked in the presence of dATP and Zn2+, but the reaction products differ in that the sugar moiety of the incorporated nucleotide appears distorted or otherwise cleaved, in agreement with reports that Zn2+ may act as a polymerase inhibitor rather than as a mutagen [Sirover, M. A., & Loeb, L. A. (1976) Science 194, 1434-1436]. Although no reaction is observed when crystals are soaked in the presence of dATP and other metal ions such as Ca2+, Co2+, Cr3+, or Ni2+, X-ray structural analyses show that these metal ions coordinate the triphosphate moiety of the nucleotide in a manner that differs from that observed with Mg2+. In addition, all metal ions tested, with the exception of Mg2+, promote a change in the side-chain position of aspartic acid 192, which is one of three highly conserved active-site carboxylate residues. Soaking experiments with nucleotides other than dATP (namely, dCTP, dGTP, dTTP, ATP, ddATP, ddCTP, AZT-TP, and dATP alpha S) reveal a non-base-specific binding site on pol beta for the triphosphate and sugar moieties of a nucleotide, suggesting a possible mechanism for nucleotide selectivity whereby triphosphate-sugar binding precedes a check for correct base pairing with the template.
About this StructureAbout this Structure
9ICS is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
A structural basis for metal ion mutagenicity and nucleotide selectivity in human DNA polymerase beta., Pelletier H, Sawaya MR, Wolfle W, Wilson SH, Kraut J, Biochemistry. 1996 Oct 1;35(39):12762-77. PMID:8841119
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