Sequence‐specific chemical modification of a 365‐nucleotide‐long DNA fragment with an alkylating oligonucleotide derivative

Abstract
An aromatic 2‐chloroethylamino group was attached to the 5'‐terminal phosphate of the oligodeoxyribonucleotide pCCCTCTTTCTT. The oligonucleotide derivative prepared was used for modification of the 365‐nucleotide‐long DNA fragment. It was found that modification of the fragment proceeds in a sequence‐specific way at 3 guanosine residues within the sequence complementary to the oligonucleotide reagent.