Effect of hyperoxidized guanine on DNA primer–template structures: Spiroiminodihydantoin leads to strand slippage

Abstract 

Oxidation of guanine in DNA can lead to mutagenic lesions such as 7-hydro-8-oxoguanine (oG). Upon further oxidation, a more mutagenic lesion, spirominodihydantoin (Sp), can occur. In this study, nuclear magnetic resonance (NMR) investigations were performed to determine the structural features of DNA primer–template models with 5′-GG, 5′-G(oG), 5′-G(Sp) and 5′-T(Sp) templates, that mimic the situation in which the downstream G of the template has been oxidized to oG or hyperoxidized to Sp. Our results show that misalignment occurs only in the 5′-G(Sp) and 5′-T(Sp) templates, providing structural insights into the observed differences in mutagenicity of Sp and oG during DNA replication.

Abbreviations: NMR, nuclear magnetic resonance, oG, 7-hydro-8-oxoguanine, Sp, spiroiminodihydantoin, dCTP, deoxycytidine triphosphate, dATP, deoxyadenosine triphosphate, 1D, one-dimensional, 2D, two-dimensional, NOE, nuclear Overhauser effect, NOESY, nuclear Overhauser effect spectroscopy, DQF, double-quantum-filtered, COSY, correlation spectroscopy, TOCSY, total correlation spectroscopy, HSQC, heteronuclear single quantum coherence spectroscopy, UV, ultra-violet, DSS, 2,2-dimethyl-2-silapentane-5-sulfonic acid, WATERGATE, water suppression by gradient-tailored excitation, PAGE, polyacrylamide gel electrophoresis, DEAE, diethylaminoethyl, NaCl, sodium chloride, NaPi, sodium phosphate, HPLC, high performance liquid chromatography, MALDI, matrix-assisted laser desorption ionization, TOF, time-of-flight, MS, mass spectrometry

Keywords: NMR, DNA, Guanine, Spiroiminodihydantoin, Strand slippage