2c22
From Proteopedia
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==Overview== | ==Overview== | ||
| - | DNA polymerases insert dATP opposite the oxidative damage product | + | DNA polymerases insert dATP opposite the oxidative damage product 7,8-dihydro-8-oxodeoxyguanosine (8-oxoG) instead of dCTP, to the extent of >90% with some polymerases. Steady-state kinetics with the Y-family Sulfolobus solfataricus DNA polymerase IV (Dpo4) showed 90-fold higher incorporation efficiency of dCTP > dATP opposite 8-oxoG and 4-fold higher efficiency of extension beyond an 8-oxoG:C pair than an 8-oxoG:A pair. The catalytic efficiency for these events (with dCTP or C) was similar for G and 8-oxoG templates. Mass spectral analysis of extended DNA primers showed >/=95% incorporation of dCTP > dATP opposite 8-oxoG. Pre-steady-state kinetics showed faster rates of dCTP incorporation opposite 8-oxoG than G. The measured K(d)(,dCTP) was 15-fold lower for an oligonucleotide containing 8-oxoG than with G. Extension beyond an 8-oxoG:C pair was similar to G:C and faster than for an 8-oxoG:A pair, in contrast to other polymerases. The E(a) for dCTP insertion opposite 8-oxoG was lower than for opposite G. Crystal structures of Dpo4 complexes with oligonucleotides were solved with C, A, and G nucleoside triphosphates placed opposite 8-oxoG. With ddCTP, dCTP, and dATP the phosphodiester bonds were formed even in the presence of Ca(2+). The 8-oxoG:C pair showed classic Watson-Crick geometry; the 8-oxoG:A pair was in the syn:anti configuration, with the A hybridized in a Hoogsteen pair with 8-oxoG. With dGTP placed opposite 8-oxoG, pairing was not to the 8-oxoG but to the 5' C (and in classic Watson-Crick geometry), consistent with the low frequency of this frameshift event observed in the catalytic assays. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Egli, M.]] | [[Category: Egli, M.]] | ||
[[Category: Irimia, A.]] | [[Category: Irimia, A.]] | ||
| - | [[Category: Loukachevitch, L | + | [[Category: Loukachevitch, L V.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: DGT]] | [[Category: DGT]] | ||
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[[Category: translesion dna polymerase]] | [[Category: translesion dna polymerase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:44:01 2008'' |
Revision as of 14:44, 21 February 2008
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EFFICIENT AND HIGH FIDELITY INCORPORATION OF DCTP OPPOSITE 7,8-DIHYDRO-8-OXODEOXYGUANOSINE BY SULFOLOBUS SOLFATARICUS DNA POLYMERASE DPO4
Overview
DNA polymerases insert dATP opposite the oxidative damage product 7,8-dihydro-8-oxodeoxyguanosine (8-oxoG) instead of dCTP, to the extent of >90% with some polymerases. Steady-state kinetics with the Y-family Sulfolobus solfataricus DNA polymerase IV (Dpo4) showed 90-fold higher incorporation efficiency of dCTP > dATP opposite 8-oxoG and 4-fold higher efficiency of extension beyond an 8-oxoG:C pair than an 8-oxoG:A pair. The catalytic efficiency for these events (with dCTP or C) was similar for G and 8-oxoG templates. Mass spectral analysis of extended DNA primers showed >/=95% incorporation of dCTP > dATP opposite 8-oxoG. Pre-steady-state kinetics showed faster rates of dCTP incorporation opposite 8-oxoG than G. The measured K(d)(,dCTP) was 15-fold lower for an oligonucleotide containing 8-oxoG than with G. Extension beyond an 8-oxoG:C pair was similar to G:C and faster than for an 8-oxoG:A pair, in contrast to other polymerases. The E(a) for dCTP insertion opposite 8-oxoG was lower than for opposite G. Crystal structures of Dpo4 complexes with oligonucleotides were solved with C, A, and G nucleoside triphosphates placed opposite 8-oxoG. With ddCTP, dCTP, and dATP the phosphodiester bonds were formed even in the presence of Ca(2+). The 8-oxoG:C pair showed classic Watson-Crick geometry; the 8-oxoG:A pair was in the syn:anti configuration, with the A hybridized in a Hoogsteen pair with 8-oxoG. With dGTP placed opposite 8-oxoG, pairing was not to the 8-oxoG but to the 5' C (and in classic Watson-Crick geometry), consistent with the low frequency of this frameshift event observed in the catalytic assays.
About this Structure
2C22 is a Single protein structure of sequence from Sulfolobus solfataricus with and as ligands. Active as DNA-directed DNA polymerase, with EC number 2.7.7.7 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Efficient and high fidelity incorporation of dCTP opposite 7,8-dihydro-8-oxodeoxyguanosine by Sulfolobus solfataricus DNA polymerase Dpo4., Zang H, Irimia A, Choi JY, Angel KC, Loukachevitch LV, Egli M, Guengerich FP, J Biol Chem. 2006 Jan 27;281(4):2358-72. Epub 2005 Nov 22. PMID:16306039
Page seeded by OCA on Thu Feb 21 16:44:01 2008
Categories: DNA-directed DNA polymerase | Single protein | Sulfolobus solfataricus | Egli, M. | Irimia, A. | Loukachevitch, L V. | CA | DGT | 7 | 8-dihydro-8-oxodeoxyguanosine | Dna damage | Dna repair | Dna replication | Dna-binding | Dna-directed dna polymerase | Magnesium | Metal -binding | Mutator protein | Nucleotidyltransferase | P2 dna polymerase iv | Transferase | Translesion dna polymerase
