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Glutamate counteracts the denaturing effect of urea through its effect on the denatured state.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2003 Sep 19; Vol. 278 (38), pp. 36077-84. Date of Electronic Publication: 2003 Jul 05. - Publication Year :
- 2003
-
Abstract
- The urea induced equilibrium denaturation behavior of glutaminyl-tRNA synthetase from Escherichia coli (GlnRS) in 0.25 m potassium l-glutamate, a naturally occurring osmolyte in E. coli, has been studied. Both the native to molten globule and molten globule to unfolded state transitions are shifted significantly toward higher urea concentrations in the presence of l-glutamate, suggesting that l-glutamate has the ability to counteract the denaturing effect of urea. d-Glutamate has a similar effect on the equilibrium denaturation of glutaminyl-tRNA synthetase, indicating that the effect of l-glutamate may not be due to substrate-like binding to the native state. The activation energy of unfolding is not significantly affected in the presence of 0.25 m potassium l-glutamate, indicating that the native state is not preferentially stabilized by the osmolyte. Dramatic increase of coefficient of urea concentration dependence (m) values of both the transitions in the presence of glutamate suggests destabilization and increased solvent exposure of the denatured states. Four other osmolytes, sorbitol, trimethylamine oxide, inositol, and triethylene glycol, show either a modest effect or no effect on native to molten globule transition of glutaminyl-tRNA synthetase. However, glycine betaine significantly shifts the transition to higher urea concentrations. The effect of these osmolytes on other proteins is mixed. For example, glycine betaine counteracts urea denaturation of tubulin but promotes denaturation of S228N lambda-repressor and carbonic anhydrase. Osmolyte counteraction of urea denaturation depends on osmolyte-protein pair.
- Subjects :
- Amino Acyl-tRNA Synthetases chemistry
Animals
Betaine pharmacology
Carbonic Anhydrases chemistry
Cattle
Dose-Response Relationship, Drug
Escherichia coli enzymology
Glutamates pharmacology
Inositol pharmacology
Kinetics
Methylamines pharmacology
Oxidants pharmacology
Potassium Chloride pharmacology
Protein Binding
Protein Conformation
Protein Denaturation
Protein Folding
Sorbitol pharmacology
Spectrophotometry
Temperature
Thermodynamics
Time Factors
Trypsin pharmacology
Tubulin chemistry
Glutamic Acid chemistry
Urea pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 278
- Issue :
- 38
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 12844489
- Full Text :
- https://doi.org/10.1074/jbc.M211207200