Electron spin resonance studies of some copper(II) peptide complexes

Abstract

Electron spin resonance studies have been made of a number of copper(II) peptides. For the copper(I) complexes of glycylglycine, diglycylglycine, and β-alanyl-L-histidine and its derivatives dimer formation takes place in frozen aqueous solutions. The application of computational procedures has enabled estimates of copper(II)–copper(II) separations to be made which are found to be compatible with structures resulting from X-ray measurements. No evidence for dimer formation at room temperature has emerged. For the 2:1 copper(II)L-cystinyl-bisglycinate complex the copper(II)–copper(II) separation is consistent with a folded conformation of the chelate.