Base-excision of a self-complementary oligonucleotide with central G:T 
mismatches by the G:T/U-specific mismatch DNA glycosylase (MUG), generates an 
unusual DNA structure which is remarkably similar in conformation to an 
interstrand DNA adduct of the anti-tumor drug cis-diamminedichloroplatinum. The 
abasic sugars generated by excision of the mismatched thymines are extruded from 
the double-helix, and the 'widowed' deoxyguanosines rotate so that their N7 and 
O6 groups protrude into the minor groove of the duplex and restack in an 
interleaved intercalative geometry, generating a kink in the helix axis.