Citation for published version (APA): Szczepankiewicz, O. (2011). To Fold or To Fibrillate? Serendipity in Stability Studies.

Transcription

1 To Fold or To Fibrillate? Serendipity in Stability Studies Szczepankiewicz, Olga 2011 Link to publication Citation for published version (APA): Szczepankiewicz, O. (2011). To Fold or To Fibrillate? Serendipity in Stability Studies. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. L UNDUNI VERS I TY PO Box L und

2 To Fold or To Fibrillate? Serendipity in Stability Studies Doctoral Thesis Olga Szczepankiewicz Lund, Sweden, 2011 Department of Biophysical Chemistry Akademisk avhandling för avläggande av teknisk doktorsexamen vid teknisk fakultet vid Lunds Universitet, att offentligt försvaras i hörsal B, Kemicentrum, fredagen den 28 oktober, kl Fakultetsopponent är professor Daniel Otzen, University of Aarhus.

3 Front cover: Sixten Westman, 4 years, To Fold or To Fibrillate? On the front you can see four folded proteins in yellow. A fibril in orange is presented on the back of the cover. Supervisor: Professor Sara Snogerup Linse Examination Committee: Assistant Professor Eva Nordberg Lund University Professor Mats Hansson Carlsberg Laboratory, Copenhagen Professor Per Hammarström Linköping University To Fold or To Fibrillate? Serendipity in Stability Studies Copyright 2011, Olga Szczepankiewicz Department of Biophysical Chemistry Lund University, Lund, Sweden Printed by Tryckeriet i E-huset, Lund, Sweden 2011 ISBN:

4 Any knowledge that doesn't lead to new questions quickly dies out: it fails to maintain the temperature required for sustaining life. Wisława Szymborska Nobel Laureate 1996

5 Dokumentblad

6 Contents Preface 1 Populärvetenskaplig sammanfattning 2 List of papers and the author s contribution to the papers 5 Additional publications not included in the thesis 6 Abbreviations 7 Acknowledgement 8 Part one: Background to proteins Introduction to proteins 11 Thermodynamics for reactions 11 Intermolecular interactions 13 van der Waals interactions 13 Coulombic interactions 13 Hydrogen bonds 14 Hydrophobic effect 14 Intramolecular interactions in proteins 16 Protein folding and stability 18 Protein denaturation 20 Thermal denaturation 21 Chemical denaturation 22 Protein binding and assembly 23

7 Protein reconstitution 24 Protein aggregation 25 To fold or to fibrillate? 26 Stabilization of proteins 27 Phage display and fragment complementation 28 Split GFP and fragment complementation 29 Part two: Experimental systems Monellin 29 Amyloid beta peptide 30 B1 domain of protein G 32 Green fluorescence protein 32 Part three: Methods Optical spectroscopy 33 Absorbance spectroscopy 33 Circular dichroism spectroscopy 34 Fluorescence spectroscopy 35 Thioflavin T fluorescence assay fibrillation kinetics 36 Part four: Introduction to papers 37 Part five: To fold or to fibrillate? Conclusions 53 Part six: References 55 Part seven: Papers