title: Density functional complexation study of metal ions with cysteine.
abstract: Metal complexes of cysteine have been studied using a density functional theory based method together with a continuum solvation model. Complexation geometries for metal complexes of cysteine with Zn(2+), Mg(2+), Ca(2+), Fe(3+), and Mn(2+) have been determined. Different coordination modes have been considered for MCys(2) and MCys(3) complexes. Complexation energies have been determined, and they have been corrected with (empirical) metal- and ligand-specific parameters, the latter of which was determined separately for Cys(N,O,S) and Cys(N,S) ligands. The results indicate that the preferred binding mode for Zn(2+) with cysteine is bidentate (N,S) type binding in tetrahedral or trigonal bipyramidal geometry while Mg(2+) and Ca(2+) prefer sulfur-free binding sites in octahedral geometry. Fe(3+) prefers binding via sulfur and nitrogen atoms, whereas for Mn(2+) several equally stable structures were found. The new correction parameters can be applied for other sulfur-containing ligands to evaluate the binding strength of a new ligand with metal ions. The observed preferences of metal ions in binding are in agreement with the previous knowledge of the behavior of metal ions.
authors: Department of Chemistry, PO Box 3000, FIN-90014 University of Oulu, Finland.
authors: Henna
authors: H
authors: Pesonen
authors: Reijo
authors: R
authors: Aksela
authors: Kari
authors: K
authors: Laasonen
mesh_terms: D002118:Calcium / Q000737:chemistry; D003198:Computer Simulation; D003545:Cysteine / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D008274:Magnesium / Q000737:chemistry; D008345:Manganese / Q000737:chemistry; D008956:Models, Chemical; D009942:Organometallic Compounds / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry
chemical_list: D009942:Organometallic Compounds; D008345:Manganese; D007501:Iron; D008274:Magnesium; D015032:Zinc; D003545:Cysteine; D002118:Calcium