2lwn

Publication Abstract from PubMed

The addition of hydroxyl radicals to the C8 position of guanine can lead to the formation of a 2,6-diamino-4-hydroxy-5-formamido-2'-deoxypyrimidine (Fapy-dG) lesion, whose endogenous levels in cellular DNA rival those of 8-oxo-7,8-dihydroxy-2'-deoxyguanosine. Despite its prevalence, the structure of duplex DNA containing Fapy-dG is unknown. We have prepared an undecameric duplex containing a centrally located beta-cFapy-dG residue paired to dC and determined its solution structure by high-resolution NMR spectroscopy and restrained molecular dynamic simulations. The damaged duplex adopts a right-handed helical structure with all residues in an anti conformation, forming Watson-Crick base pair alignments, and 2-deoxyribose conformations in the C2'-endo/C1'-exo range. The formamido group of Fapy rotates out of the pyrimidine plane and is present in the Z and E configurations that equilibrate with an approximate 2:1 population ratio. The two isomeric duplexes show similar lesion-induced deviations from a canonical B-from DNA conformation that are minor and limited to the central three-base-pair segment of the duplex, affecting the stacking interactions with the 5-lesion-neighboring residue. We discuss the implications of our observations for translesion synthesis during DNA replication and the recognition of Fapy-dG by DNA glycosylases.

Solution structure of duplex DNA containing a beta-Carba-Fapy-dG lesion.,Lukin M, Zaliznyak T, Attaluri S, Johnson F, de Los Santos C Chem Res Toxicol. 2012 Nov 19;25(11):2423-31. doi: 10.1021/tx300290b. Epub 2012, Aug 29. PMID:22897814^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.