Linked Life Data

21534566

Source:http://linkedlifedata.com/resource/pubmed/id/21534566

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
2011-5-25
pubmed:abstractText
Proteins perform their functions in cells where macromolecular solutes reach concentrations of >300 g/L and occupy >30% of the volume. The volume excluded by these macromolecules stabilizes globular proteins because the native state occupies less space than the denatured state. Theory predicts that crowding can increase the ratio of folded to unfolded protein by a factor of 100, amounting to 3 kcal/mol of stabilization at room temperature. We tested the idea that volume exclusion dominates the crowding effect in cells using a variant of protein L, a 7 kDa globular protein with seven lysine residues replaced by glutamic acids; 84% of the variant molecules populate the denatured state in dilute buffer at room temperature, compared with 0.1% for the wild-type protein. We then used in-cell NMR spectroscopy to show that the cytoplasm of Escherichia coli does not overcome even this modest (?1 kcal/mol) free-energy deficit. The data are consistent with the idea that nonspecific interactions between cytoplasmic components can overcome the excluded-volume effect. Evidence for these interactions is provided by the observations that adding simple salts folds the variant in dilute solution but increasing the salt concentration inside E. coli does not fold the protein. Our data are consistent with the results of other studies of protein stability in cells and suggest that stabilizing excluded-volume effects, which must be present under crowded conditions, can be ameliorated by nonspecific interactions between cytoplasmic components.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1520-5126
pubmed:author
pubmed:copyrightInfo
© 2011 American Chemical Society
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
133
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
8082-5
pubmed:dateRevised
2011-10-26
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Macromolecular crowding fails to fold a globular protein in cells.
pubmed:affiliation
Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural