Department of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
Phys Chem Chem Phys. 2014 Apr 14;16(14):6568-74. doi: 10.1039/c3cp55411b. Epub 2014 Feb 26.
Cleavage of the O-P bond in 8-bromo-2'-deoxyguanosine-3',5'-diphosphate (BrdGDP), considered as a model of single strand break (SSB) in labelled double-stranded DNA (ds DNA), is investigated at the B3LYP/6-31++G(d,p) level. The thermodynamic and kinetic characteristics of the formation of SSB are compared to those related to the 5',8-cycloguanosine lesion. The first reaction step, common to both damage types, which is the formation of the reactive guanyl radical, proceeds with a barrier-free or low-barrier release of the bromide anion. The guanyl radical is then stabilized by hydrogen atom transfer from the C3' or C5' sites of the 2'-deoxyribose moiety to its C8 center. The C3' path, via the O-P bond cleavage, leads to a ketone derivative (the SSB model), while the C5' path is more likely to yield 5',8-cycloguanosine.
在 B3LYP/6-31++G(d,p) 水平上研究了 8-溴-2'-脱氧鸟苷-3'，5'-二磷酸（BrdGDP）中 O-P 键的断裂，该化合物被认为是标记的双链 DNA（dsDNA）中单链断裂（SSB）的模型。比较了形成 SSB 的热力学和动力学特征与与 5'，8-环鸟苷损伤相关的特征。两种损伤类型的第一步反应，即反应性鸟苷自由基的形成，通过溴化物阴离子的无势垒或低势垒释放进行。然后，鸟苷自由基通过氢原子从 2'-脱氧核糖部分的 C3'或 C5'位点转移到其 C8 中心来稳定。C3'途径通过 O-P 键断裂导致酮衍生物（SSB 模型），而 C5'途径更可能产生 5'，8-环鸟苷。
