Proteins acquire their unique functions through specific folding of their linear polypeptide chains. Misfolding results in numerous diseases, such as cystic fibrosis and various neurodegenerative disorders. Although a great deal of work has been done on the investigation of how the secondary and tertiary structures of proteins are formed and both experimental and theoretical techniques for studying protein folding are continually becoming more refined, a quantitative and predictive understanding of protein folding is still not attainable. There are still many fundamental questions such as: How do specific and nonspecific interactions determine the folding pathways, the roughness of the energy landscape, the thermally and kinetically accessible conformation substates? On what range of timescales do particular conformational and folding events occur? Addressing these questions presents the need for further studies with static and time-resolved spectroscopic techniques that can provide the necessary time resolutions and structure sensitivities. The principal objective of the proposed research is therefore to develop new spectroscopic methods and new conformational probes that can be used to generate detailed structure interpretations of the stable and transient folding species and their dynamics over the time range of interest. A detailed set of experiments are planned to gain new insight into the understanding of various aspects of the protein folding problem. The technical goals are to: (a) develop a millisecond stopped-flow infrared spectrometer;(b) further develop new spectroscopic methods based on unnatural amino acids for protein folding and binding studies;(c) study the hidden intermediate in protein folding;(d) study the evolution of protein folding kinetics;(e) study the conformational and folding dynamics of single protein molecules. Achieving these specific aims should result in not only new experimental methods for protein folding and binding studies but also new insights into the understanding of many fundamental issues in protein folding, thus making practical and direct contributions to the field.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
3R01GM065978-08S2
Application #
7935876
Study Section
Macromolecular Structure and Function B Study Section (MSFB)
Program Officer
Wehrle, Janna P
Project Start
2009-09-30
Project End
2010-08-31
Budget Start
2009-09-30
Budget End
2010-08-31
Support Year
8
Fiscal Year
2009
Total Cost
$86,109
Indirect Cost
Name
University of Pennsylvania
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Lin, Chun-Wei; Gai, Feng (2017) Microscopic nucleation and propagation rates of an alanine-based ?-helix. Phys Chem Chem Phys 19:5028-5036
Abaskharon, Rachel M; Gai, Feng (2016) Direct measurement of the tryptophan-mediated photocleavage kinetics of a protein disulfide bond. Phys Chem Chem Phys 18:9602-7
Ding, Bei; Hilaire, Mary Rose; Gai, Feng (2016) Infrared and Fluorescence Assessment of Protein Dynamics: From Folding to Function. J Phys Chem B 120:5103-13
Abaskharon, Rachel M; Gai, Feng (2016) Meandering Down the Energy Landscape of Protein Folding: Are We There Yet? Biophys J 110:1924-32
Mukherjee, Debopreeti; Gai, Feng (2016) Exciton circular dichroism couplet arising from nitrile-derivatized aromatic residues as a structural probe of proteins. Anal Biochem 507:74-8
Mintzer, Mary Rose; Troxler, Thomas; Gai, Feng (2015) p-Cyanophenylalanine and selenomethionine constitute a useful fluorophore-quencher pair for short distance measurements: application to polyproline peptides. Phys Chem Chem Phys 17:7881-7
Ma, Jianqiang; Pazos, Ileana M; Zhang, Wenkai et al. (2015) Site-specific infrared probes of proteins. Annu Rev Phys Chem 66:357-77
Hilaire, Mary Rose; Abaskharon, Rachel M; Gai, Feng (2015) Biomolecular Crowding Arising from Small Molecules, Molecular Constraints, Surface Packing, and Nano-Confinement. J Phys Chem Lett 6:2546-53
Pazos, Ileana M; Ahmed, Ismail A; Berríos, Mariana I León et al. (2015) Sensing pH via p-cyanophenylalanine fluorescence: Application to determine peptide pKa and membrane penetration kinetics. Anal Biochem 483:21-6
Oh, Kwang-Im; Smith-Dupont, Kathryn B; Markiewicz, Beatrice N et al. (2015) Kinetics of peptide folding in lipid membranes. Biopolymers 104:281-90

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