[Chemical reactions in double-helical nucleic acids. X. Kinetics of oligomer condensation under the effect of synthetic water-soluble carbodiimides].

: Chemical ligation of oligonucleotides in double stranded complexes has been considered in its structural-kinetic aspect. In a study of the reactivity of eleven synthetic water soluble carbodiimides the reaction rate has been found to be strongly affected by the substituents at N1 and N3 atoms. The chemical ligation appears to involve the linear form of carbodiimide. Model systems have been used to assess the rate constant for the phosphate activation. The ratio of kinetic constants for the productive and nonproductive reactions of the activated derivate apparently reflects the reactive site conformation; for a given duplex this parameter is virtually independent of the condensing agent structure.