Abstract

We are studying the effects of salts and pH on the stability of apo-flavodoxin and some of its fragments. Previously we have demonstrated that the stability of apo-flavodoxin measured by urea denaturation at pH 7 is salt dependent. More recently, we have established that the effect is specific for Na+ salts. This effect has also been found in a fragment of apo-flavodoxin containing residues 1-139. In order to further characterize the physical basis of this cation effect, we are studying the thermodynamics of unfolding by DSC under a variety of ionic conditions. The structure of apo-flavodoxin has been solved recently and we will attempt to simulate the effects of cations on the stability of this protein with algorithms designed to identify cation binding sites and to calculate the energetics of cation binding.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR004328-10
Application #
6122047
Study Section
Project Start
1997-08-05
Project End
1998-08-04
Budget Start
Budget End
Support Year
10
Fiscal Year
1997
Total Cost
Indirect Cost

  Institution

Name
Johns Hopkins University
Department
Type
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218

  Publications

Jaganaman, Sunil; Pinto, Alex; Tarasev, Michael et al. (2007) High levels of expression of the iron-sulfur proteins phthalate dioxygenase and phthalate dioxygenase reductase in Escherichia coli. Protein Expr Purif 52:273-9
Todd, M J; Gomez, J (2001) Enzyme kinetics determined using calorimetry: a general assay for enzyme activity? Anal Biochem 296:179-87
Karantza, V; Freire, E; Moudrianakis, E N (2001) Thermodynamic studies of the core histones: stability of the octamer subunits is not altered by removal of their terminal domains. Biochemistry 40:13114-23
Griko, Y V; Remeta, D P (1999) Energetics of solvent and ligand-induced conformational changes in alpha-lactalbumin. Protein Sci 8:554-61
Chu, V; Freitag, S; Le Trong, I et al. (1998) Thermodynamic and structural consequences of flexible loop deletion by circular permutation in the streptavidin-biotin system. Protein Sci 7:848-59
Luque, I; Freire, E (1998) Structure-based prediction of binding affinities and molecular design of peptide ligands. Methods Enzymol 295:100-27
Luque, I; Gomez, J; Semo, N et al. (1998) Structure-based thermodynamic design of peptide ligands: application to peptide inhibitors of the aspartic protease endothiapepsin. Proteins 30:74-85
Gomez, J; Semo, N; Freire, E (1998) Structural thermodynamic study of the binding of renin inhibitors to endothiapepsin. Adv Exp Med Biol 436:325-8
Koder, R L; Miller, A F (1998) Overexpression, isotopic labeling, and spectral characterization of Enterobacter cloacae nitroreductase. Protein Expr Purif 13:53-60
Freire, E (1998) Statistical thermodynamic linkage between conformational and binding equilibria. Adv Protein Chem 51:255-79

Showing the most recent 10 out of 86 publications