Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


case1080747299.pdf (2.68 MB)

ETD Abstract Container

Abstract Header

Folding of the Prion Protein

Apetri, Constantin Adrian
http://rave.ohiolink.edu/etdc/view?acc_num=case1080747299

Abstract Details

2004, Doctor of Philosophy, Case Western Reserve University, Chemistry.
Propagation of transmissible spongiform encephalopathies is believed to involve the conversion of the cellular prion protein, PrPC, into a misfolded oligomeric form,PrPSc. An important step towards understanding the mechanism of this conversion is to study the folding pathway(s) and the stability of PrPC. In the first part of this work, we examined the kinetics of folding and unfolding reactions for the recombinant wild type human prion protein fragment 90–231. The stopped flow data provided clear evidence for the existence of an intermediate on the refolding pathway of the prion protein as indicated by a pronounced curvature in chevron plots and the presence of significant burst phase amplitudes in the refolding kinetics. The protein folding studies were then extended to prion protein variants carrying mutations associated with inherited prion diseases. Analysis of kinetic data clearly indicates the presence of partially structured intermediates on the refolding pathway of each PrP variant studied. For the majority of PrP variants tested, mutations linked to familial prion diseases resulted in a pronounced increase in the thermodynamic stability – and thus the population – of the folding intermediate. These data strongly suggest that partially folded intermediates of PrP may play a crucial role in prion protein conversion, serving as direct precursors of the pathogenic PrPSc isoform. Previous studies indicate that salts promote the conformational conversion of the recombinant prion protein into a PrPSc-like form. To gain insight into the mechanism of this effect, we studied the influence of a number of salts on the thermodynamic stability of the recombinant human prion protein. Chemical unfolding studies in urea showed that at low concentrations (< 50 mM), all salts tested significantly reduced the thermodynamic stability of the protein. At higher salt concentrations, the destabilizing effect was gradually reversed, and salts acted according to their ranking in the Hofmeister series. The observations indicate that electrostatic interactions play an unusually important role in the stability of the prion protein and that ions present in the cellular environment may control the PrPC to PrPSc conversion by modulating the thermodynamic stability of the native PrPC isoform.
Witold Surewicz (Advisor)
181 p.
Biophysics, Medical
protein folding; prion diseases; prion protein; folding intermediate; salt effect; kinetics; stopped flow

Recommended Citations

Citations

  • Apetri, C. A. (2004). Folding of the Prion Protein [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1080747299

    APA Style (7th edition)

  • Apetri, Constantin. Folding of the Prion Protein. 2004. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1080747299.

    MLA Style (8th edition)

  • Apetri, Constantin. "Folding of the Prion Protein." Doctoral dissertation, Case Western Reserve University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1080747299

    Chicago Manual of Style (17th edition)

case1080747299
3,471
© 2004, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.