FACTORS INFLUENCING THE EXTENT AND REGIOSPECIFICITY OF CROSS-LINK FORMATION BETWEEN SINGLE-STRANDED-DNA AND REACTIVE COMPLEMENTARY OLIGODEOXYNUCLEOTIDES

Cross-link formation, within the duplex, by oligodeoxynucleotides cont aining a [omega-(omega-haloacylamido)alkyl]-2'-deoxyuridine to a compl ementary oligodeoxynucleotide was investigated under conditions approx imating the physiologic environment. The site and extent of crosslinki ng to the target strand were determined for several electrophilic halo acylamidoalkyl structures. The regiospecificity of alkylation was prim arily determined by the length of the electrophilic haloacylamidoalkyl group, while the extent of reaction was dependent upon both the struc ture of the acylamidoalkyl group and the reactivity of the electrophil e. Cross-linking was additionally modulated by the sequence of the dup lex in the vicinity of the alkylation site. The exact placement of the electrophile adjacent to the targeted nucleophile, an N-7 group on a specific guanine base in the target strand, was the most important fac tor in determining the rate of reaction. With the optimal haloacylamid oalkyl structure and duplex sequence, the most rapid rate obtained was t1/2 = 1.3 h at 37-degrees-C.