title: Probing ion/molecule interactions in aqueous solutions with vibrational energy transfer.
abstract: Interactions between model molecules representing building blocks of proteins and the thiocyanate anion, a strong protein denaturant agent, were investigated in aqueous solutions with intermolecular vibrational energy exchange methods. It was found that thiocyanate anions are able to bind to the charged ammonium groups of amino acids in aqueous solutions. The interactions between thiocyanate anions and the amide groups were also observed. The binding affinity between the thiocyanate anion and the charged amino acid residues is about 20 times larger than that between water molecules and the amino acids and about 5-10 times larger than that between the thiocyanate anion and the neutral backbone amide groups. The series of experiments also demonstrates that the chemical nature, rather than the macroscopic dielectric constant, of the ions and molecules plays a critical role in ion/molecule interactions in aqueous solutions.
authors.affiliation: Department of Chemistry, Rice University, Houston, Texas 77005, USA.
authors.forename: Jiebo
authors.initials: J
authors.lastname: Li
authors.forename: Hongtao
authors.initials: H
authors.lastname: Bian
authors.forename: Xiewen
authors.initials: X
authors.lastname: Wen
authors.forename: Hailong
authors.initials: H
authors.lastname: Chen
authors.forename: Kaijun
authors.initials: K
authors.lastname: Yuan
authors.forename: Junrong
authors.initials: J
authors.lastname: Zheng
mesh_terms: D000577:Amides / Q000737:chemistry*; D000596:Amino Acids / Q000737:chemistry*; D000838:Anions / Q000737:chemistry; D004735:Energy Transfer; D008958:Models, Molecular; D012996:Solutions; D013861:Thiocyanates / Q000737:chemistry*; D014732:Vibration; D014867:Water / Q000737:chemistry
chemical_list: D000577:Amides; D000596:Amino Acids; D000838:Anions; D012996:Solutions; D013861:Thiocyanates; D014867:Water; C031760:thiocyanate