Models for enzyme-copper-nucleic acid interaction ¹H NMR line broadening study of the interaction of some copper complexes with cytidine

Abstract

Sodium (salicylideneglycylglycinato) copper(II), bis(2,9-dimethyl-1, 10-phenanthroline)copper (II), and (1,5-bis (benzimidazol-2-yl)-3-thiapentane) copper(II) were interacted with cytidine in D₂O. For all the complexes, the broadening of the¹H signals of cytidine is found to be in the order H(5)>H(6)>H(1'); this suggests the binding of N (3) and O² sites of cytidine to copper. The possibility that the ribose moiety is also involved in coordination cannot be ruled out. The complete broadening of the H(5) signals for the last complex above is because of the coordinative unsaturation of the complex. It has been concluded that steric factors and coordinative unsaturation in athe complexes affect the extent of interaction with cytidine.