This laboratory is engaged in studies on protein structure and the mechanism of protein folding. The main subject of research is swine pepsinogen, a monomeric protein of molecular weight= 39,630, which is stable at pH's between 6 and 8.5. Below pH 6 pepsinogen activates itself by proteolytic loss of its first 44 amino acids, to produce an enzymatically active protein, pepsin. Pepsin is stable on at pH's below 6. Pepsin and pepsinogen are unfolded by exposure to high pH, temperature or concentrations of denaturants, such as urea. However, unfolded pepsinogen can refold to its normal structure, when returned to native conditions, whereas pepsin cannot. I am interested in the mechanism of this refolding reaction and how the difference in sequence influences the refolding of the two proteins. We have used techniques such as ultra-violet, circular dichroic and fluorescence spectroscopies, together with chemical modification and peptide chemistry, to characterize the structures of the native and unfolded species. We have used rapid kinetic techniques, such as stopped-flow and T-jump, to detect partly folded forms in the folding reaction; their structures have been partially determined and the nature of the chemical reactions which separate them from the native and unfolded forms investigated.

Project Start
Project End
Budget Start
Budget End
Support Year
1
Fiscal Year
1993
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Indirect Cost
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United States
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McPhie, Peter; Ni, Yi-sheng; Minton, Allen P (2006) Macromolecular crowding stabilizes the molten globule form of apomyoglobin with respect to both cold and heat unfolding. J Mol Biol 361:7-10
Jang, Ming Y; Yarborough 3rd, Orlando H; Conyers, Gary B et al. (2005) Stable secondary structure near the nicking site for adeno-associated virus type 2 Rep proteins on human chromosome 19. J Virol 79:3544-56
Handa, Vaishali; Yeh, Herman J C; McPhie, Peter et al. (2005) The AUUCU repeats responsible for spinocerebellar ataxia type 10 form unusual RNA hairpins. J Biol Chem 280:29340-5
Britto, P J; Knipling, Leslie; McPhie, Peter et al. (2005) Thiol-disulphide interchange in tubulin: kinetics and the effect on polymerization. Biochem J 389:549-58
Miller, Lance D; McPhie, Peter; Suzuki, Hideyo et al. (2004) Multi-tissue gene-expression analysis in a mouse model of thyroid hormone resistance. Genome Biol 5:R31
McPhie, Peter (2004) CD studies on films of amyloid proteins and polypeptides: quantitative g-factor analysis indicates a common folding motif. Biopolymers 75:140-7
Kalinin, Andrey E; Idler, William W; Marekov, Lyuben N et al. (2004) Co-assembly of envoplakin and periplakin into oligomers and Ca(2+)-dependent vesicle binding: implications for cornified cell envelope formation in stratified squamous epithelia. J Biol Chem 279:22773-80
Sasahara, Kenji; McPhie, Peter; Minton, Allen P (2003) Effect of dextran on protein stability and conformation attributed to macromolecular crowding. J Mol Biol 326:1227-37
Ahmed, S Ashraf; McPhie, Peter; Smith, Leonard A (2003) Autocatalytically fragmented light chain of botulinum a neurotoxin is enzymatically active. Biochemistry 42:12539-49
Kamiya, Yuji; Puzianowska-Kuznicka, Monika; McPhie, Peter et al. (2002) Expression of mutant thyroid hormone nuclear receptors is associated with human renal clear cell carcinoma. Carcinogenesis 23:25-33

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