Linked Life Data

8381493

Source:http://linkedlifedata.com/resource/pubmed/id/8381493

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1993-3-11
pubmed:abstractText
Despite considerable effort there is no consensus as to what interaction, or set of interactions, provides the dominant force that drives protein folding and specifies folded protein structures. A key thermodynamic observation is that a large drop in heat capacity (delta Cp) usually accompanies folding in water. Various factors may contribute to this effect, especially changes in the structure of the solvent upon exposure of both non-polar and polar groups in the unfolded state. The unfavourable Gibbs free energy of solvating non-polar groups, in particular, is thought to provide a central driving force for folding (the hydrophobic effect) but the role of solvent ordering in this remains a matter of controversy. We report here a series of experiments that show that a protein can fold into its native conformation under conditions where solvent ordering effects are demonstrably negligible. In methanol/water mixtures ubiquitin unfolds reversibly with a delta Cp value that falls close to zero above about 30% (v/v) methanol. We are able to reason, on the basis of these data, that the net contribution to the heat capacity change arising primarily from the protein structure itself is not significant and that contributions from changes in solvent ordering are rendered negligible by the change in composition. Nuclear magnetic resonance measurements, however, indicate that non-polar side-chains do still become exposed to solvent in the denatured state under these conditions. The combination of these results and model compound studies suggests that the elimination of ordering effects is an intrinsic property of the mixed solvent. We can, therefore, conclude that the solvent ordering component of the hydrophobic effect is not an obligatory factor in determining the three-dimensional structure into which the protein will fold.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
229
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
502-11
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Protein folding in the absence of the solvent ordering contribution to the hydrophobic interaction.
pubmed:affiliation
Department of Biochemistry, Cambridge, U.K.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't