Interaction of cysteine with Cu2+ and group IIb (Zn2+, Cd2+, Hg2+) metal cations: a theoretical study

✍ Scribed by M. Belcastro; T. Marino; N. Russo; M. Toscano

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 208 KB
• Volume: 40
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/jms.755

✦ Synopsis

Abstract

The structure and energetics of complexes obtained upon interaction between cysteine and Zn^2+^, Cd^2+^, Hg^2+^ and Cu^2+^ cations were studied using quantum chemical density functional theory calculations with the 6–311++G** orbital basis set and relativistic pseudopotentials for the cations. Different coordination sites for metal ions on several cysteine conformers were considered. In their lowest energy complexes with the amino acid, the Zn^2+^ and Cd^2+^ cations appear to be three‐coordinated to carbonyl oxygen, nitrogen and sulfur atoms, whereas the Cu^2+^ and Hg^2+^ ions are coordinated to both the carbonyl oxygen and sulfur atoms of one of the zwitterion forms of the amino acid. Bonds of metal cations with the coordination sites are mainly ionic except those established with sulfur, which show a small covalent character that become most significant when Cu^2+^ and Hg^2+^ are involved. The order of metal ion affinity proposed is Cu > Zn > Hg > Cd. Copyright © 2005 John Wiley & Sons, Ltd.