1TK5

T7 DNA polymerase binary complex with 8 oxo guanosine in the templating strand

Summary for 1TK5

• Entry DOI: 10.2210/pdb1tk5/pdb
• Related: 1T8E 1TK0
• Descriptor: 5'-D(*CP*GP*AP*AP*A*GP*CP*CP*AP*GP*TP*GP*CP*CP*AP*(DDG)P*TP*GP*CP*AP*A)-3', 5'-D(*CP*CP*CP*(8OG)P*CP*TP*GP*GP*CP*AP*CP*TP*GP*GP*CP*CP*GP*TP*CP*GP*TP*TP*TP*TP*CP*G)-3', DNA polymerase, ... (9 entities in total)
• Functional Keywords: 8-oxoguanosine dna polymerase, transferase-electron transport-dna complex, transferase/electron transport/dna
• Biological source: Enterobacteria phage T7; More
• Total number of polymer chains: 4
• Total formula weight: 106130.58

Authors

Brieba, L.G.,Eichman, B.F.,Kokoska, R.J.,Doublie, S.,Kunkel, T.A.,Ellenberger, T. (deposition date: 2004-06-08, release date: 2004-08-31, Last modification date: 2023-08-23)

Primary citation

Brieba, L.G.,Eichman, B.F.,Kokoska, R.J.,Doublie, S.,Kunkel, T.A.,Ellenberger, T.
Structural basis for the dual coding potential of 8-oxoguanosine by a high-fidelity DNA polymerase.
Embo J., 23:3452-3461, 2004

PubMed Abstract: Accurate DNA replication involves polymerases with high nucleotide selectivity and proofreading activity. We show here why both fidelity mechanisms fail when normally accurate T7 DNA polymerase bypasses the common oxidative lesion 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8oG). The crystal structure of the polymerase with 8oG templating dC insertion shows that the O8 oxygen is tolerated by strong kinking of the DNA template. A model of a corresponding structure with dATP predicts steric and electrostatic clashes that would reduce but not eliminate insertion of dA. The structure of a postinsertional complex shows 8oG(syn).dA (anti) in a Hoogsteen-like base pair at the 3' terminus, and polymerase interactions with the minor groove surface of the mismatch that mimic those with undamaged, matched base pairs. This explains why translesion synthesis is permitted without proofreading of an 8oG.dA mismatch, thus providing insight into the high mutagenic potential of 8oG.

PubMed: 15297882
DOI: 10.1038/sj.emboj.7600354

Experimental method

X-RAY DIFFRACTION (2.2 Å)