Work

Changes in Water Structure Induced by the Guanidinium Cation and Implications for Protein Denaturation

Year: 2008

Type: article

Abstract: The effect of the guanidinium cation on the hydrogen bonding strength of water was analyzed using temperature-excursion Fourier transform infrared spectra of the OH stretching vibration in 5% H 2O/95% D 2O solutions containing a range of different guanidine-HCl and guanidine-HBr concentrations. Our findings indicate that the guanidinium cation causes the water H-bonds in solution to become more linear than those found in bulk water, and that it also inhibits the response of the H-bond network to increased temperature. Quantum chemical calculations also reveal that guanidinium affects both the charge distribution on water molecules directly H-bonded to it as well as the OH stretch frequency of H-bonds in which that water molecule is the donor. The implications of our findings to hydrophobic solvation and protein denaturation are discussed.

Source: The Journal of Physical Chemistry A

DOI: 10.1021/jp8058239

Authors: J. Nathan Scott, Nathaniel V. Nucci, Jane M. Vanderkooi

Institution: University of Pennsylvania

Language: English

Topic: Spectroscopy and Quantum Chemical Studies

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: U.S. Public Health Service, National Institute of General Medical Sciences, National Institute of Neurological Disorders and Stroke

Awards: Structural biology & molecular biophysics training program, Principles of Energy Transduction in Proteins, Water Structuring by Neurohormones, G6430267613