title: [Cleavage of a double-stranded DNA target by bleomycin derivatives of oligonucleotides, forming a ternary complex].
abstract: Hexadecathymidylate derivatives, containing covalently-bound antitumor antibiotic bleomycin A5, were shown to form a triple-helix complex with double-strand 30-bp DNA-target and to carry out within this complex complementary-addressed DNA modification. Fivefold excess of reagent in relation to target leads to non-specific cleavage mainly of pyrimidine-rich DNA strand. Total degrees of the target-strand cleavage by 5'- and 3'-bleomycin derivatives of hexadecathymidylate were 25 and 35% for purine-rich strand and 47 and 36% for pyrimidine-rich strand. Degrees of non-specific cleavage by 5'-bleomycin derivative of hexadecanucleotide that does not form triple-helix were 6 and 16% for purine- and pyrimidine-rich strands, respectively. Comparison of these data has shown that site-specific cleavage prevailed nonspecific one. Triplex of 5'-bleomycin derivative with DNA melted by 5 degrees C lower (m.p. 40 degrees C) than the similar triplex of hexadecathymidylate. Temperature lowering from 50 to 20 degrees C increases the DNA-cleavage degree according to the increase in the part of target molecules involved in triple-helix formation.
authors.forename: D S
authors.initials: DS
authors.lastname: Sergeev
authors.forename: T S
authors.initials: TS
authors.lastname: Godovikova
authors.forename: V F
authors.initials: VF
authors.lastname: Zarytova
mesh_terms: D001483:Base Sequence; D001761:Bleomycin / Q000737:chemistry / Q000494:pharmacology*; D004247:DNA / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D006868:Hydrolysis; D008969:Molecular Sequence Data
chemical_list: D001761:Bleomycin; D004247:DNA