Influence of Cu+ on the RS-NO bond dissociation energy of S-nitrosothiols.
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.
Baciu
Cristina
C
Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada.
Cho
Kyung-Bin
KB
Gauld
James W
JW
D003300:Copper / Q000737:chemistry*; D026403:S-Nitrosothiols / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013499:Surface Properties; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D026403:S-Nitrosothiols; D012996:Solutions; D014867:Water; D003300:Copper