The denatured state of a protein is implicated in a number of disease states, and plays a functionally important role in such biologically important process as transport across membranes, protein degradation and protein folding. It is the long-term goal of this work to elucidate the thermodynamic properties of the denatured ensemble, and thereby understand how these properties relate to the compactness of the denatured state, and to the denaturation Gibbs energy changes used in assessing the stability of proteins. This project will focus on a class of proteins whose denatured ensembles continue to change their thermodynamic characters as a function of denaturant concentration. The """"""""variable"""""""" thermodynamic behavior of the denatured ensembles of such proteins contrasts dramatically with the """"""""fixed"""""""" behavior exhibited by proteins whose denatured ensembles do not change their thermodynamic properties as a function of denaturant. Potentiometric titrations of native and denatured ensembles, as well as proton uptake/release measurements, will be used to: (1) distinguish """"""""variable"""""""" from """"""""fixed"""""""" thermodynamic behavior of denatured ensembles, and (2) to provide a model-independent means of evaluating the Gibbs energy differences between native and/or denatured states of proteins with related sequences. Size exclusion chromatography will also be used, to correlate dimensional changes in a denatured ensemble with that ensemble's thermodynamic properties, as a function of denaturant concentration. Our ultimate aim is to provide a strong foundation for thermodynamic measurements of protein stability, a foundation that at present is weak or invalid for many proteins.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM060292-02
Application #
6343083
Study Section
Molecular and Cellular Biophysics Study Section (BBCA)
Program Officer
Wehrle, Janna P
Project Start
2000-01-01
Project End
2003-12-31
Budget Start
2001-01-01
Budget End
2001-12-31
Support Year
2
Fiscal Year
2001
Total Cost
$155,871
Indirect Cost
Name
University of Texas Medical Br Galveston
Department
Biochemistry
Type
Schools of Medicine
DUNS #
041367053
City
Galveston
State
TX
Country
United States
Zip Code
77555