Dokument: Untersuchung von kompatible Soluten induzierter Stabilisation von Membranproteinen mittels Rasterkraftspektroskopie.
| Titel: | Untersuchung von kompatible Soluten induzierter Stabilisation von Membranproteinen mittels Rasterkraftspektroskopie. | |||||||
| Weiterer Titel: | Compatible solute induced stabilisation of membrane proteins studied by single molecule force spectroscopy | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=26569 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20130823-083631-4 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Roy Choudhury, Arpita [Autor] | |||||||
| Dateien: |
| |||||||
| Beitragende: | Prof. Dr. med. Häussinger, Dieter [Gutachter] Prof. Dr. Willbold, Dieter [Gutachter] | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 570 Biowissenschaften; Biologie | |||||||
| Beschreibung: | Compatible solutes are small organic molecules produced and accumulated by microorganisms inside their cell to counteract different kinds of environmental stress. These are known for their uncharged, zwitter ionic and osmotically active nature. Compatible solutes show osmotic activity which even at molar concentrations do not interfere with cell metabolism and rather protect the cell against osmotic imbalance. It has also been shown that oral doses of some of the osmolytes monitored in patients with hepatic disorders have shown positive responses.
These molecules significantly affect the thermodynamic equilibrium properties of proteins and are often used for studying the structure and dynamics of protein folding mechanism playing a vital role in determining the stability of the protein. But most of such studies involved ensemble measurements and only very recently single molecules techniques are being used for investigating protein stability. Mechanical single molecule techniques offer exciting possibilities for investigating protein folding and stability in native environments at sub-nanometer resolutions. The single molecules without inherent symmetry can directly be monitored in their physiological conditions using atomic force microscopy (AFM). The aim of this work was to investigate the stabilising effects of compatible solutes, ectoine, betaine and taurine on the membrane protein Bacteriorhodopsin at different concentrations. Using Atomic Force Microscopy based Force Spectroscopy their impact was quantified by measuring the forces required to pull the protein out of the membrane and the change in the persistence length of the unfolded polypeptide chain. Increasing unfolding forces were observed indicating the strengthening of intra-molecular interactions, which are vital for the protein stability. A decrease in persistence length was recorded showing the increasing tendencies of the polypeptide strand to coil up. Interestingly, it was revealed that these molecules have different stabilising effects on protein unfolding at different concentrations. This allows us to predict the mechanism of interaction between the unfolded polypeptide chain of Bacteriorhodopsin and the osmolyte. The osmolytes are expelled from the protein surface due to the increase in chemical potential of the exposed stretched state forcing the protein to acquire a more compact structure. This information is aimed to achieve a better understanding of the interaction between the unfolded protein and the solutes. The results show that the unfolding of single proteins provides in-depth and crucial information about their structure-dynamic relationship at sub-nanometer scale and will open new paths for our further studies regarding the effects of compatible solutes on other membrane proteins. We expect that these results can further provide information which can directly resolve the transient intermediate states and multiple reaction pathways. Additionally, the results can be useful for studies related to the characterization of the complex dynamics of protein folding. Thus, this study is set to provide exciting possibilities in the field of drug development for liver diseases including in vitro rescue of the misfolded proteins and to directly analyze and correlate their structural and functional properties at the sub-molecular level. | |||||||
| Lizenz: |  Urheberrechtsschutz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Biologie » Physikalische Biologie | |||||||
| Dokument erstellt am: | 23.08.2013 | |||||||
| Dateien geändert am: | 23.08.2013 | |||||||
| Promotionsantrag am: | 04.06.2013 | |||||||
| Datum der Promotion: | 10.07.2013 |
