The long term aim of this project is to understand the mechanism by which specific interactions within proteins contribute to their overall stability. To this end, the goal of the proposed research is to identify and quantitate native-state interactions that are responsible for stability of ovomucoid third domain, a small globular protein. Using hydrogen exchange, the aim understand how highly localized changes in sequence, such as a single amino acid substitutions, can lead to global changes in protein stability. Stabilizing interactions will be identified by correlation of hydrogen exchange behavior with the thermodynamics of third domain folding.
The first aim i s examination of the behavior of amide protons (NHs) are likely to be exchanging only when the protein is completely unfolded and, hence, ar reporting on the most stable regions in ovomucoid third domain.
The second aim i s an investigation of the role of specific electrostatic interactions in third domain stability.
The third aim i s quantitation of additional types of specific interactions through thermodynamic and hydrogen exchange studies of third domain variants. Identification and quantitation of specific stabilizing interactions in proteins will increase our understanding of the factors responsible for stability. This will, in turn, lead to a) improved design of proteins with increased stability, b) enhanced capabilities for the design of new proteins, c) a valuable quantitative data base for theoreticians, and d) a better understanding of how the amino acid sequence dictates the folding and stability of proteins.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM046869-04
Application #
2184355
Study Section
Molecular and Cellular Biophysics Study Section (BBCA)
Project Start
1992-02-01
Project End
1997-01-31
Budget Start
1995-02-01
Budget End
1996-01-31
Support Year
4
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of Iowa
Department
Biochemistry
Type
Schools of Medicine
DUNS #
041294109
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Sidhu, Arshdeep; Surolia, Avadhesha; Robertson, Andrew D et al. (2011) A hydrogen bond regulates slow motions in ubiquitin by modulating a ýý-turn flip. J Mol Biol 411:1037-48
Ferraro, Debra M; Robertson, Andrew D (2008) Predicting the magnitude of the reflex response to insertions in ubiquitin. J Mol Biol 375:764-72
Ferraro, Debra M; Ferraro, Daniel J; Ramaswamy, S et al. (2006) Structures of ubiquitin insertion mutants support site-specific reflex response to insertions hypothesis. J Mol Biol 359:390-402
Jensen, Jan H; Li, Hui; Robertson, Andrew D et al. (2005) Prediction and rationalization of protein pKa values using QM and QM/MM methods. J Phys Chem A 109:6634-43
Li, Hui; Robertson, Andrew D; Jensen, Jan H (2005) Very fast empirical prediction and rationalization of protein pKa values. Proteins 61:704-21
Ferraro, Debra M; Hope, Erin K; Robertson, Andrew D (2005) Site-specific reflex response of ubiquitin to loop insertions. J Mol Biol 352:575-84
Scott, Patricia M; Bilodeau, Patricia S; Zhdankina, Olga et al. (2004) GGA proteins bind ubiquitin to facilitate sorting at the trans-Golgi network. Nat Cell Biol 6:252-9
Li, Hui; Robertson, Andrew D; Jensen, Jan H (2004) The determinants of carboxyl pKa values in turkey ovomucoid third domain. Proteins 55:689-704
Ferraro, Debra M; Lazo, Noel D; Robertson, Andrew D (2004) EX1 hydrogen exchange and protein folding. Biochemistry 43:587-94
Bilodeau, Patricia S; Winistorfer, Stanley C; Kearney, William R et al. (2003) Vps27-Hse1 and ESCRT-I complexes cooperate to increase efficiency of sorting ubiquitinated proteins at the endosome. J Cell Biol 163:237-43

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