Sequence-specific modification of guanosine in DNA by a C60-linked deoxyoligonucleotide: Evidence for a non-singlet oxygen mechanism

Abstract A C 60 -linked deoxyoligonucleotide (C 60 -DON-1) was prepared from bromoacetate 3 . This C 60 -oligonucleotide conjugate was hybridized to a complementary single-stranded DNA. This system reacted with light and oxygen to damage only guanosines in the single-stranded region which are closest to C 60 . The damage did not involve 1 O 2 as the active species but rather resulted from a single electron-transfer mechanism between guanosine and 3 C 60 , as shown by comparison experiments with eosin-attached DON-1 and by the use of singlet oxygen quenchers.