Origins of stereospecificity in DNA damage by anti-benzo[a]pyrene diol-epoxides. A molecular modelling study

A general computational procedure for the modelling of intercalated DNA-ligand complexes has been developed, and is used here to model intercalated complexes of the (+)-anti and (-)-anti enantiomers of benzo[a]pyrene diol-epoxide (BPDE) with cytosine-3',5'-guanosine double-stranded DNA sequences (dCpG). Results are presented indicating differences between the behaviours of the two enantiomers which have implications for the understanding of the stereospecificity of DNA strand breakage by benzo[a]pyrene diol-epoxides.