Photoreaction of 5-halouracil-containing Z-form DNA.

Photoreactions of IU-containing Z-form DNA were investigated. By introducing 8-methylguanine, stable Z-form IU-containing oligonucleotides were prepared. DNA conformational change from B to Z leads to the remarkable acceleration of the photoreactivity of IU-containing oligonucleotides. In particular 2'-hydrogen abstraction was observed preferentially in Z-form DNA, and 2'-hydroxylation occurred specifically at the 5' side of IU in Z-form DNA.