Dokument: Synthesis of Amphiphilic Glycomacromolecules and their Incorporation into Synthetic Membranes for Systematic Variation and Control of Membrane Dynamics
| Titel: | Synthesis of Amphiphilic Glycomacromolecules and their Incorporation into Synthetic Membranes for Systematic Variation and Control of Membrane Dynamics | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=70412 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20250806-124828-6 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Blawitzki, Luca-Cesare [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Hartmann, Laura [Gutachter] Prof. Dr. Monzel, Cornelia [Gutachter] | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 540 Chemie | |||||||
| Beschreibung: | The glycocalyx is a dense and highly complex layer of carbohydrates covering the plasma membrane of eukaryotic cells. While it is critically involved in a plethora of biological processes that unfold on the cellular membrane, such as pathogen infection, cellular communication or proliferation, it constantly adapts to an ever-changing environment. Due to the intricate complexity of the glycocalyx, it is challenging, if not impossible, to examine glycocalyx-related phenomena comprehensively in vivo. However, gaining a deeper understanding of the mechanisms that are related to the sugary coat on eukaryotic cell surfaces is critical to comprehend the intricate mechanisms that are closely related to health and disease.
Since natural glycans are challenging to purify and characterize, researchers have long employed synthetic mimetics of cell-surface presented glycans to study protein-glycan interactions with well defined structural compositions. However, these individual inspections fundamentally lack the impact of surrounding glycocalyx-constituents and, hence, cannot reflect the complexity of the glycocalyx as a holistic entity. In order to investigate glycocalyx-associated processes more realistically, glycocalyx mimetics, simplified model systems that mirror key features of native glycocalyces and allow to systematically study certain phenomena, have consequently been developed. Such mimetics employ synthetic phospholipid bilayers (e.g. giant unilamellar vesicles or supported phospholipid bilayers) to mimic the cell membrane, as well as lipid-tethered glycan mimetics that intercalate into the membrane, yielding three-dimensional surrogates of native cellular surfaces. While such glycocalyx mimetics bear the potential to create realistic models of the incredibly complex glycocalyx, they still lack the fundamental features of native glycocalyces, such as its crowded and dynamic nature, the large number of different glycan-constituents, as well as its spatially resolved order. To tackle this lack in structural diversity and encompassing complexity, this thesis presents different methods to prepare highly tailorable glycan mimetics (employing Solid-Phase Polymer Synthesis (SPPoS) and a recently introduced novel type of controlled radical polymerization (TIRP)), subsequently allowing for the construction of more realistic models of the glycocalyx. In the first part of the thesis, cholesteryl-tethered heteromultivalent short and long glycomimetics are synthesized and incorporated into GUVs to construct crowded glycocalyx mimetics. Heteromultivalent mixtures of binding and non-binding ligands are employed to investigate the impact of crowding on glycan-lectin mediated adhesion, showing that the relative adhesion strength depends on the macromolecular structure and the overall density of the glycomimetics in the membrane. The second part of the thesis focuses on mimicking lipid rafts, locally resolved membrane regions that are believed to regulate cellular processes. Homomultivalent short glycan mimetics with different membrane-anchors, differing in their physico-chemical properties, are prepared and shown to selectively localize in either ordered (Lo) or disordered (Ld) membrane domains in phase separating GUVs. The presentation of the ligands in Lo is shown to drastically increase lectin recruitment, shedding light on the putative function of lipid rafts in native cellular membranes. In the third part of the thesis, a protocol to prepare long and short mimetics of sulfated glycosaminoglycans (sGAGs) is developed. sGAGs in nature are exploited by pathogenic microorganisms, such as viruses, to serve as an initial contact for infection. Reconstitution of these sGAGs in glycocalyx mimetics hence enables the examination of virus-sGAG-interactions in a highly controlled setting. Finally, the last part of the thesis focuses on the dynamic clustering of glycans in native glycocalyces. Therefore, an SPPoS-compatible building block comprising a polymerizable diacetylene-moiety is developed and introduced into the macromolecular backbone of glycan mimetics. Subsequent incorporation into GUVs then allows to trace lectin-mediated glycan mimetic-clustering, mimicking dynamic glycan clustering in native cellular membranes. Overall this thesis substantially enhances the existing portfolio of glycocalyx mimetics by providing highly tailorable glycan mimetics and provides new approaches for constructing glycocalyx models to contribute to the understanding of fundamental question in glycobiology and membrane biophysics. | |||||||
| Lizenz: |  Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Chemie » Organische Chemie und Makromolekulare Chemie | |||||||
| Dokument erstellt am: | 06.08.2025 | |||||||
| Dateien geändert am: | 06.08.2025 | |||||||
| Promotionsantrag am: | 19.02.2025 | |||||||
| Datum der Promotion: | 28.07.2025 |
