Ab initio Calculations for Exploring Metal Ion-(Gly-Gly-His) Complexes

Abstract

The specific interactions in metal ion-peptide systems have been studied in many research groups. It is known that the coordinated metal ions play a significant role in the biological action of peptide. Several experimental techniques have been applied to present of specific interactions in metal ion-peptide complexes. Theoretical approaches about metal-oligopeptide structure and metal-ligand coordination geometry have been also performed by molecular dynamics simulations and ab initio calculations.9-13 Studies have focused on the structural data of metal ion-ligand complexes. Four-coordination geometries were mainly discussed because they are most frequently encountered in the metal-binding sites of metalloproteins. Two-and six-coordination geometries were also considered.10,11 Several groups reported the interactions between the special oligopeptides of three or four amino acid residues and metal ion because those oligopeptides are principally capable of providing the saturated (four electron donor atoms) equatorial binding site. 1,2,6,13 In this study, our attention is focused on the interaction between the oligopeptide of three amino acid residues (GlyGly-His) and metal ion without solvent effect. (The response of the Gly-Gly-His modified electrode to Cu 2+ ion was measured as a current in the solution experiment of Fisher et al..2 ) The interaction between Gly-Gly-His and metal ion is studied by optimized structures and stabilization energies in ab initio calculations. Ab initio calculations are performed with 6-31G(d) and 6-311+G(d,p) basis sets to determine optimized structures and stabilization energies. Density functional theory(DFT) at B3LYP level is carried out using Gaussian98 14 series of program. The optimized structures and the stabilization energies between Gly-Gly-His and metal ions (Ca

Electrochemical Investigations into the Binding of Some Nonredox Active Metal Ions to Surface-Bound Glutamic Acid Conjugates

“…For the Cu-binding oligopeptide Gly-Gly-His, a Cu 2+ specific electrochemical response was observed down to the sub-ppt level . Ab initio calculations indicate that binding of the metal to the backbone Ns is responsible for the selectivity …”