title: Influence of Cu+ on the RS-NO bond dissociation energy of S-nitrosothiols.
abstract: Density functional theory methods have been used to investigate the role and effects of Cu+ binding to the S and N centers of the -SNO functional group within S-nitrosothiols (RSNOs), on the lability of the NO group. The binding of Cu+ to the S center is found to weaken the S-N bond, while the N-O bond is concomitantly strengthened, consistent with the notion that Cu+ binding catalyzes NO radical release. In contrast, however, the binding of Cu+ to the N center is found to dramatically shorten and strengthen the S-N bond with a concomitant lengthening of the N-O bond, suggesting stabilization of the RSNOs against NO release. Upon solvation, complexes with Cu+ bound to the N center are stabilized relative to the corresponding S-bound complexes, though remaining slightly higher in energy. The barriers to interconversion between corresponding isomers were also investigated. Implications for biochemical regulation of NO release from RSNOs are discussed.
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario 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*; D026403:S-Nitrosothiols / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013499:Surface Properties; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D026403:S-Nitrosothiols; D012996:Solutions; D014867:Water; D003300:Copper