Stereospecific formation of the (R)-[gamma]-hydroxytrimethylene interstrand [N.sup.2]-dG:[N.sup.2]-dG cross-link arising from the [gamma]-OH-1,[N.sup.2]-propano-2'-deoxyguanosine adduct in the 5'-CpG-3' DNA sequence

The structure of the stereochemically favored (R)-[gamma]-hydroxytrimethylene [N.sup.2]-dG:[N.sup.2]-dG interstran DNA cross-link in the 5'-CpG-3' DNA sequence is described. The formation of the hydrogen bond has explained the thermal stability of the carbinolamine interstrand cross-link and the stereochemical preference for the (R) configuration of the cross-link.