Impact of urea on water structure: A clue to its properties as a denaturant?

A. K. Soper, Ed Castner, Alenka Luzar

Research output: Contribution to journalArticle

146 Citations (Scopus)

Abstract

A new investigation of the structure of urea-water solutions at a mole ratio of 1 urea to 4 water molecules is described. Neutron diffraction is used in conjunction with isotope labelling on the water and urea hydrogen atoms and on the nitrogen atom of urea. The diffraction data are analysed using the empirical potential structure refinement procedure to yield a set of site-site radial distribution functions and spatial density functions that are consistent with the diffraction data. The results are discussed in relation to recent and past X-ray and neutron diffraction experiments and theoretical studies of this system. It is found that urea incorporates readily into water, forming pronounced hydrogen bonds with water at both the amine and carbonyl headgroups. In addition the urea also hydrogen bonds to itself, forming chains or clusters consisting of up to approximately 60 urea molecules in a cluster. There, is however, little or no evidence of urea segregating itself from water, in marked contrast to a recent study of the methanol-water system. This behaviour is discussed in the context of the great propensity of urea to effect protein denaturation.

Original languageEnglish
Pages (from-to)649-666
Number of pages18
JournalBiophysical Chemistry
Volume105
Issue number2-3
DOIs
Publication statusPublished - Sep 1 2003

Fingerprint

ureas
Urea
Water
water
Neutron Diffraction
Hydrogen
Neutron diffraction
neutron diffraction
Hydrogen bonds
Diffraction
diffraction
hydrogen bonds
Isotope Labeling
Protein Denaturation
Atoms
Denaturation
Molecules
biopolymer denaturation
radial distribution
X-Ray Diffraction

Keywords

  • Hydration
  • Isotope substitution
  • Neutron diffraction
  • Protein denaturation

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Biophysics

Cite this

Impact of urea on water structure : A clue to its properties as a denaturant? / Soper, A. K.; Castner, Ed; Luzar, Alenka.

In: Biophysical Chemistry, Vol. 105, No. 2-3, 01.09.2003, p. 649-666.

Research output: Contribution to journalArticle

Soper, A. K. ; Castner, Ed ; Luzar, Alenka. / Impact of urea on water structure : A clue to its properties as a denaturant?. In: Biophysical Chemistry. 2003 ; Vol. 105, No. 2-3. pp. 649-666.
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