title: Sulfur K-edge X-ray absorption spectroscopy as an experimental probe for S-nitroso proteins.
abstract: X-ray absorption spectroscopy at the sulfur K-edge (2.4-2.6keV) provides a sensitive and specific technique to identify S-nitroso compounds, which have significance in nitric oxide-based cell signaling. Unique spectral features clearly distinguish the S-nitroso-form of a cysteine residue from the sulfhydryl-form or from a methionine thioether. Comparison of the sulfur K-edge spectra of thiolate, thiol, thioether, and S-nitroso thiolate compounds indicates high sensitivity of energy positions and intensities of XAS pre-edge features as determined by the electronic environment of the sulfur absorber. A new experimental setup is being developed for reaching the in vivo concentration range of S-nitroso thiol levels in biological samples.
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA. Szilagyi@Montana.EDU <Szilagyi@Montana.EDU>
authors.forename: Robert K
authors.initials: RK
authors.lastname: Szilagyi
authors.forename: David E
authors.initials: DE
authors.lastname: Schwab
mesh_terms: D015335:Molecular Probes; D009603:Nitroso Compounds / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D013057:Spectrum Analysis; D013455:Sulfur / Q000737:chemistry*; D014965:X-Rays
chemical_list: D015335:Molecular Probes; D009603:Nitroso Compounds; D011506:Proteins; D013455:Sulfur