CHLORINE-35 NUCLEAR MAGNETIC RESONANCE STUDY OF ZINC NUCLEOTIDE DIPHOSPHATE COMPLEXES

In 0.5 M NaCl solutions, Zn(II)-nucleotide diphosphate complexes increase the 35Cl nuclear relaxation rate. The added relaxation is due to the formation of Zn(II)-Cl- bonds and has been studied by measuring the 35Cl nmr line width. The relaxation produced by unprotonated nucleotide diphosphate complexes is dependent on the nucleotide base structure. Maximum line broadening was found for the adenosine diphosphate complex, Zn-(ADP)-, while the inosine diphosphate complex, Zn(IDP)-, has the least effect. The relaxation produced by a given complex is influenced by protonation of the NDP ligand or by hydrolysis of the metal ion. The formation of Zn(ADP)24- is evident. The results strongly suggest that Zn2+ is chelated between the nucleotide base and phosphate chain in Zn(ADP)- but is chelated only to the phosphate chain in Zn(IDP)-. © 1969, American Chemical Society. All rights reserved.