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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.

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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 13.00. Fakultetsopponent är professor Daniel Otzen, University of Aarhus.

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: 978-91-7422-280-7

“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

Dokumentblad

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

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