1QKG

DNA DECAMER DUPLEX CONTAINING T-T DEWAR PHOTOPRODUCT

Summary for 1QKG

• Entry DOI: 10.2210/pdb1qkg/pdb
• Related: 1CFL
• NMR Information: BMRB: 4409
• Descriptor: DNA (5'-D(*CP*GP*CP*AP*(HYD)TP*+TP*AP*CP*GP*C)-3'), DNA (5'-D(*GP*CP*GP*TP*GP*AP*TP*GP*CP*G)-3') (2 entities in total)
• Functional Keywords: deoxyribonucleic acid, dna photoproduct, dewar product, (6-4) adduct, mutagenesis, translesion replication, dna
• Total number of polymer chains: 2
• Total formula weight: 6110.04

Authors

Lee, J.-H.,Bae, S.-H.,Choi, Y.-J.,Choi, B.-S. (deposition date: 1999-07-20, release date: 2000-05-11, Last modification date: 2024-06-19)

Primary citation

Lee, J.-H.,Bae, S.-H.,Choi, B.-S.
The Dewar Photoproduct of Thymidylyl(3'-->5')-Thymidine (Dewar Product) Exhibits Mutagenic Behavior in Accordance with the "A Rule".
Proc.Natl.Acad.Sci.USA, 97:4591-, 2000

PubMed Abstract: In contrast to the highly mutagenic pyrimidine(6-4)pyrimidone photoproduct, its Dewar valence isomer (Dewar product) has low mutagenic potential and produces a broad range of mutations [LeClerc, J. E., Borden, A. & Lawrence, C. W. (1991) Proc. Natl. Acad. Sci. USA 88, 9685-9689]. To determine the origin of the mutagenic property of the Dewar product, we used experimental NMR restraints and molecular dynamics to determine the solution structure of a Dewar-lesion DNA decamer duplex. This DNA decamer duplex (DW/GA duplex) contains a mismatched base pair between the 3' T residue of the Dewar lesion (T6) and an opposed G residue (G15). The 3' T (T6) of the Dewar lesion formed stable hydrogen bonds with the opposing G15 residue. However, the helical bending and unwinding angles of the DW/GA duplex were much larger than those of a second duplex that contains the Dewar lesion and opposing A15 and A16 residues (DW/AA duplex). The DW/GA duplex showed poorer stacking interactions at the two bases of the Dewar product and at the adjacent A7 small middle dotT14 base pair than did the DW/AA duplex. These structural features imply that no thermal stability or conformational benefit is obtained by incorporating a G instead of an A opposite the 3' T of the Dewar lesion. These properties may thus facilitate the preferential incorporation of an A in accordance with the A rule during translesion replication and lead to the low frequency of 3' T-->C mutations observed at this site.

PubMed: 10758155
DOI: 10.1073/PNAS.080057097

Experimental method

SOLUTION NMR