Abstract
The formation of the complexes formed by Ni II and Zn II with Asp-Asp-Asp and a series of tetrapeptides containing one or two Asp residues or one Glu residue are reported. Stability constants were measured pH-metrically. The particular species and the metal ion binding sites were determined using 1H NMR, UV-vis and CD spectroscopy. The β-carboxylate group of the Asp residue stabilizes the complexes significantly, particularly when present as the N-terminal residue. As a result the tendency for Ni II to deprotonate and bind to amide-nitrogen atoms, forming planar diamagnetic complexes, is reduced and their formation delayed to a significantly higher pH when compared to other peptides. The side chain of the Glu residue has a much smaller effect. As anticipated, Zn II was unable to deprotonate and bind to peptide nitrogens.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call