title: Collective hydration dynamics of guanidinium chloride solutions and its possible role in protein denaturation: a terahertz spectroscopic study.
abstract: The remarkable ability of guanidinium chloride (GdmCl) to denature proteins is a well studied yet controversial phenomenon; the exact molecular mechanism is still debatable, especially the role of hydration dynamics, which has been paid less attention. In the present contribution, we have addressed the issue of whether the collective hydrogen bond dynamics of water gets perturbed in the presence of GdmCl and its possible impact on the denaturation of a globular protein human serum albumin (HSA), using terahertz (THz) time domain spectroscopy (TTDS) in the frequency range of 0.3-2.0 THz. The collective hydrogen bond dynamics is determined by fitting the obtained complex dielectric response in a multiple Debye relaxation model. To compare the results, the studies were extended to two more salts: tetramethylguanidinium chloride (TMGdmCl) and sodium chloride (NaCl). It was concluded that the change in hydration dynamics plays a definite role in the protein denaturation process.
authors.affiliation: Department of Chemical, Biological and Macromolecular Sciences, S.N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700098, India. rajib@bose.res.in.
authors.forename: Nirnay
authors.initials: N
authors.lastname: Samanta
authors.forename: Debasish Das
authors.initials: DD
authors.lastname: Mahanta
authors.forename: Rajib Kumar
authors.initials: RK
authors.lastname: Mitra
mesh_terms: D019791:Guanidine / Q000737:chemistry*; D006146:Guanidines / Q000737:chemistry; D006801:Humans; D006860:Hydrogen Bonding; D056004:Molecular Dynamics Simulation; D011489:Protein Denaturation; D012709:Serum Albumin / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D012996:Solutions; D055068:Terahertz Spectroscopy; D014867:Water / Q000737:chemistry*
chemical_list: D006146:Guanidines; D012709:Serum Albumin; D012996:Solutions; D014867:Water; D012965:Sodium Chloride; D019791:Guanidine; C477069:1,1,3,3-tetramethylguanidine