title: Ring complexes of S-nitrosothiols with CU+: a density functional theory study.
abstract: The density functional theory (DFT) method B3P86/6-311+G(2df,p) has been employed to investigate the complexes formed upon interaction of Cu(+) with nitrosylated cysteine (CysNO) and its decarboxylated (H(2)NCH(2)CH(2)SNO) and deaminated (HOOCCH(2)CH(2)SNO) derivatives. Optimized structures, relative enthalpies and relative free energies have been calculated and compared. In addition, the effects of binding an H(2)O molecule to the Cu(+) centre in the resulting complexes have also been considered. It is found that the most stable complexes are formed when Cu(+) coordinates to the S-nitrosothiol via S of the SNO group. This results in dramatic lengthenings of the SN bond with concomitant shortening of the NO bond. In contrast, when Cu(+) coordinates via the nitrogen of the SNO group, a shortening of the SN bond with lengthening of the NO bond is observed. These effects are tempered by the electron donating ability of other functional groups also coordinated with the Cu(+) centre in the complexes and on the coordination state of the Cu(+) ion.
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada.
authors.forename: Cristina
authors.initials: C
authors.lastname: Baciu
authors.forename: Kyung-Bin
authors.initials: KB
authors.lastname: Cho
authors.forename: James W
authors.initials: JW
authors.lastname: Gauld
mesh_terms: D003300:Copper / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry; D020030:Nitric Oxide Donors / Q000737:chemistry*; D026403:S-Nitrosothiols / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D020030:Nitric Oxide Donors; D026403:S-Nitrosothiols; D003300:Copper; D003545:Cysteine