Dokument: Sequence-defined oligo(amidoamines) for the multivalent presentation of natural and non-natural binding motifs and their protein interactions
| Titel: | Sequence-defined oligo(amidoamines) for the multivalent presentation of natural and non-natural binding motifs and their protein interactions | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=59601 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20220517-113222-2 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Pasch, Peter [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Hartmann, Laura [Gutachter] Prof. Dr. Müller, Thomas J. J. [Gutachter] | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 540 Chemie | |||||||
| Beschreibung: | The aim of this work was the synthesis of monodisperse sequence-defined macromolecules, so-called precision macromolecules, which selectively combine supramolecular binding motifs, carbohydrate ligands and AIE luminophores. Four different groups of precision macromolecules were synthesized using literature-known protocols for solid-phase polymer synthesis and copper(I)- mediated azide-alkyne conjugation reactions (CuAAC). The precision macromolecules were used as ligands or inhibitors in protein binding. In addition, they have the ability to enable readout of binding or clustering events through their conjugated AIE luminophores.
In the first part of the dissertation, a novel inhibition mechanism of the oncologically relevant protease Taspase1 was investigated. For this purpose, different homomultivalent as well as heteromultivalent guanidiniocarbonylpyrrole (GCP)-containing ligands with and without additional PEG block were synthesized. In the binding assay using SPR experiments with immobilized Taspase1, binding in the mM range was detected only for the trivalent homo- and heteromultivalent macromolecules by S. Ueclue. Subsequent in vitro pull-down assays by A. Höing examined the inhibitory effects of the ligands, and only the PEGylated ligands interfered with the interactions of Taspase1 with its partner protein Importin in a concentration-dependent manner. The first part of this dissertation showed how difficult it is to detect binding events. Therefore, the second part of this work aimed to perform a systematic study using AIE luminophores to read out ligand-protein binding events. Therefore, five monovalent GCP ligands with AIE luminophore were synthesized. The unique feature of the five structures is that they are all based on a combination of sequence-defined oligo(amidoamine) scaffolds, a conjugated GCP, and an AIE luminophore, with the position of the luminophore varying from the immediate vicinity of the binding motif to the middle of the side or main chain to the end group. All macromolecules were systematically investigated for their fluorescence properties, both in solution and in the solid state, and for their AIE behavior upon binding to various natural and synthetic polyanions. Surprisingly, only one of the macromolecules showed a clear AIE behavior, demonstrating indeed that the position of the AIE within the ligand structure affects the function of the ligand for detection. In the third part of this work, AIE glycomimetics were synthesized and subsequently used to study carbohydrate-protein interactions. Starting from a weak initial fluorescence of the two structures in aqueous medium, changes in emission as well as turbidity could be studied by titrating different lectins. For the tetrameric lectins Con A, GNA, and the dimeric lectin PSA, an increase in emission and turbidity was obtained with the Mannose derivative, leading to an AIE probe. Only for the dimer LCA, no increase in turbidity and emission was obtained. Moreover, this study showed that a cluster effect of the AIE ligand with the lectins is required to obtain a pronounced aggregation-induced emission signal, as a correlation of emission and turbidity was clearly demonstrated. In the previous part, glycooligomers equipped with AIE luminophores showed AIE effects with different lectins, but also that cluster effects take on a key function. To further investigate cluster effects, amphiphilic sequence-defined glycosurfactants were synthesized in the fourth part, where the agglomeration of surfactants into micelles and their dissolution were studied by fluorescence spectroscopy. Here it was shown that by adding SDS (sodium dodecyl sulfate) to the micelle system, the fluorescence intensity decreased due to fewer interactions of the AIE moieties. In the future, the AIE surfactants could be used for the detection of lectins or even clusters in membranes if it becomes possible to enhance their AIE effect by binding. | |||||||
| Lizenz: |  Urheberrechtsschutz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Chemie » Organische Chemie und Makromolekulare Chemie | |||||||
| Dokument erstellt am: | 17.05.2022 | |||||||
| Dateien geändert am: | 17.05.2022 | |||||||
| Promotionsantrag am: | 08.04.2022 | |||||||
| Datum der Promotion: | 08.04.2022 |
