It is generally recognized that the H-exchange behavior of the amide NH of a protein can yield information about structure, structure change, and structural dynamics all through the protein, but this capability has not yet been achieved. We have developed differential H-exchange methods that can label just those parts of any protein that participate in any interaction (allosteric change, small or large molecule binding, etc.). Recent advances in NMR now make it probable that one will be able to recognize many of the amide NH resonances in a protein like cytochrome c, and measure their individual exchange rates. The coupling of the HX and NMR capabilities would provide a most powerful tool for protein chemical studies. We propose to begin to develop this capability. The selective labelling methods will be used, with samples of fully ND-exchanged protein, to put H on just those segments of cytochrome c that act to adjust the redox potential of the heme, or that interact with the oxidase, or the reductase, etc. Then we will attempt to identify the sensitive (protonated) resonances using 2D NMR techniques supplemented by our selective tritium-labelling and peptide HPLC separation methods. We further suspect that measurement of the H-exchange rates of restricted sets of NH like these will distinguish between alternative models for the internal dynamical motions suggested to determine protein H-exchange processes. If the local unfolding model is confirmed, as now seems likely (at least for a-helices), then experiments like these will also be able to quantify the contribution of individual segments to protein function in terms of free energy. We hope to check this capability by comparing redox sensitive H-exchange changes in related cytochromes having differing redox potentials.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM031847-02
Application #
3280232
Study Section
Biophysics and Biophysical Chemistry B Study Section (BBCB)
Project Start
1983-12-01
Project End
1988-11-30
Budget Start
1984-12-01
Budget End
1985-11-30
Support Year
2
Fiscal Year
1985
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Ye, Xiang; Mayne, Leland; Kan, Zhong-Yuan et al. (2018) Folding of maltose binding protein outside of and in GroEL. Proc Natl Acad Sci U S A 115:519-524
Nguyen, David; Mayne, Leland; Phillips, Michael C et al. (2018) Reference Parameters for Protein Hydrogen Exchange Rates. J Am Soc Mass Spectrom 29:1936-1939
Tischer, Alexander; Machha, Venkata R; Frontroth, Juan P et al. (2017) Enhanced Local Disorder in a Clinically Elusive von Willebrand Factor Provokes High-Affinity Platelet Clumping. J Mol Biol 429:2161-2177
Chetty, Palaniappan S; Mayne, Leland; Lund-Katz, Sissel et al. (2017) Helical structure, stability, and dynamics in human apolipoprotein E3 and E4 by hydrogen exchange and mass spectrometry. Proc Natl Acad Sci U S A 114:968-973
Mayne, Leland (2016) Hydrogen Exchange Mass Spectrometry. Methods Enzymol 566:335-56
Hu, Wenbing; Kan, Zhong-Yuan; Mayne, Leland et al. (2016) Cytochrome c folds through foldon-dependent native-like intermediates in an ordered pathway. Proc Natl Acad Sci U S A 113:3809-14
Englander, S Walter; Mayne, Leland; Kan, Zhong-Yuan et al. (2016) Protein Folding-How and Why: By Hydrogen Exchange, Fragment Separation, and Mass Spectrometry. Annu Rev Biophys 45:135-52
Casina, Veronica C; Hu, Wenbing; Mao, Jian-Hua et al. (2015) High-resolution epitope mapping by HX MS reveals the pathogenic mechanism and a possible therapy for autoimmune TTP syndrome. Proc Natl Acad Sci U S A 112:9620-5
Englander, S Walter; Mayne, Leland (2014) The nature of protein folding pathways. Proc Natl Acad Sci U S A 111:15873-80
Chetty, Palaniappan Sevugan; Nguyen, David; Nickel, Margaret et al. (2013) Comparison of apoA-I helical structure and stability in discoidal and spherical HDL particles by HX and mass spectrometry. J Lipid Res 54:1589-97

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