{"id":{"repo_id":"tu-berlin","oai_identifier":"oai:depositonce.tu-berlin.de:11303/24313"},"canonical_url":"https://search.dev.ndltd.org/etd/tu-berlin/oai:depositonce.tu-berlin.de:11303/24313","repository":{"repo_id":"tu-berlin","name":"Technische Universität Berlin","base_url":"https://api-depositonce.tu-berlin.de/server/oai/request"},"display":{"title":"Application of thermodynamic principles in biocatalytic synthesis of novel nucleoside analogues","abstract":"Nucleosides and analogues thereof are central molecules in modern cancer therapy and in the fight against viral infections. However, their efficient synthesis is a challenging task for synthetic chemistry. This necessitates lengthy routes and results in low atom economy. Nature’s chemistry set, on the other hand, is set up to work with the high density of functional groups of nucleosides. Nucleoside phosphorylases are known to be very regio- and stereospecific enzymes. They are part of the nucleoside salvage pathway and perform nucleoside synthesis in an impressively selective way. This makes them interesting enzymes to study concerning the chemical space they cover. In this regard, the potential of thermophilic nucleoside phosphorylases is especially intriguing due to their high stability under challenging conditions. However, the range of enzymatically accessible nucleoside analogues is underexplored and biocatalytic nucleoside synthesis has not yet reached industrial relevance. Recently, the thermodynamic rules of these reactions have been elucidated, but these findings have not been applied to actual reactions yet. This work aims to highlight the added value of biocatalytic approaches in nucleoside chemistry. To this end, the enzymes were challenged with non-natural substrates and the equilibrium constants of these reaction set-ups were determined. This made it possible to optimize reactions to obtain yield-wastebalanced processes. Using this approach, di-halogenated purine nucleosides, 4’-thionucleosides, an unexpected N7-xanthosine and various ribavirin derivates were synthesized and purified in milligram yields. The cytotoxicity in human cell lines was evaluated for selected examples. In conclusion, it is confirmed that thermophilic nucleoside phosphorylases exhibit an impressive substrate scope. This enables straight-forward diversification reactions from simple starting molecules. In this work this is exemplified by the biocatalytic synthesis of fifteen, so far undescribed, nucleoside analogues. Both sugar- and base modifications are accessible. This signifies a tremendous advantage over traditional chemical syntheses.","abstract_html":"Nucleosides and analogues thereof are central molecules in modern cancer therapy and in the fight against viral infections. However, their efficient synthesis is a challenging task for synthetic chemistry. This necessitates lengthy routes and results in low atom economy. Nature’s chemistry set, on the other hand, is set up to work with the high density of functional groups of nucleosides. Nucleoside phosphorylases are known to be very regio- and stereospecific enzymes. They are part of the nucleoside salvage pathway and perform nucleoside synthesis in an impressively selective way. This makes them interesting enzymes to study concerning the chemical space they cover. In this regard, the potential of thermophilic nucleoside phosphorylases is especially intriguing due to their high stability under challenging conditions. However, the range of enzymatically accessible nucleoside analogues is underexplored and biocatalytic nucleoside synthesis has not yet reached industrial relevance. Recently, the thermodynamic rules of these reactions have been elucidated, but these findings have not been applied to actual reactions yet. This work aims to highlight the added value of biocatalytic approaches in nucleoside chemistry. To this end, the enzymes were challenged with non-natural substrates and the equilibrium constants of these reaction set-ups were determined. This made it possible to optimize reactions to obtain yield-wastebalanced processes. Using this approach, di-halogenated purine nucleosides, 4’-thionucleosides, an unexpected N7-xanthosine and various ribavirin derivates were synthesized and purified in milligram yields. The cytotoxicity in human cell lines was evaluated for selected examples. In conclusion, it is confirmed that thermophilic nucleoside phosphorylases exhibit an impressive substrate scope. This enables straight-forward diversification reactions from simple starting molecules. In this work this is exemplified by the biocatalytic synthesis of fifteen, so far undescribed, nucleoside analogues. Both sugar- and base modifications are accessible. This signifies a tremendous advantage over traditional chemical syntheses.","abstract_has_math":false,"creators":["Westarp, Sarah"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Neubauer, Peter"],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025","date_published":"2025","updated_at":"2026-07-27T21:28:29Z","subjects":[],"languages":["en"],"rights":[],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://doi.org/10.14279/depositonce-23127"],"render_values":[{"text":"https://doi.org/10.14279/depositonce-23127","href":"https://doi.org/10.14279/depositonce-23127","code":true}]}]},"links":{"outbound_url":"https://depositonce.tu-berlin.de/handle/11303/24313","outbound_label":"Repository record","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Neubauer, Peter"]},{"key":"dc:creator","label":"Author","values":["Westarp, Sarah"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-04-15T13:48:15Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-04-15T13:48:15Z"]},{"key":"dc:date.issued","label":"Date","values":["2025"]},{"key":"dc:type","label":"Dc Type","values":["Doctoral Thesis"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://depositonce.tu-berlin.de/handle/11303/24313","https://doi.org/10.14279/depositonce-23127"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Nucleosides and analogues thereof are central molecules in modern cancer therapy and in the fight against viral infections. However, their efficient synthesis is a challenging task for synthetic chemistry. This necessitates lengthy routes and results in low atom economy. Nature’s chemistry set, on the other hand, is set up to work with the high density of functional groups of nucleosides. Nucleoside phosphorylases are known to be very regio- and stereospecific enzymes. They are part of the nucleoside salvage pathway and perform nucleoside synthesis in an impressively selective way. This makes them interesting enzymes to study concerning the chemical space they cover. In this regard, the potential of thermophilic nucleoside phosphorylases is especially intriguing due to their high stability under challenging conditions. However, the range of enzymatically accessible nucleoside analogues is underexplored and biocatalytic nucleoside synthesis has not yet reached industrial relevance. Recently, the thermodynamic rules of these reactions have been elucidated, but these findings have not been applied to actual reactions yet. This work aims to highlight the added value of biocatalytic approaches in nucleoside chemistry. To this end, the enzymes were challenged with non-natural substrates and the equilibrium constants of these reaction set-ups were determined. This made it possible to optimize reactions to obtain yield-wastebalanced processes. Using this approach, di-halogenated purine nucleosides, 4’-thionucleosides, an unexpected N7-xanthosine and various ribavirin derivates were synthesized and purified in milligram yields. The cytotoxicity in human cell lines was evaluated for selected examples. In conclusion, it is confirmed that thermophilic nucleoside phosphorylases exhibit an impressive substrate scope. This enables straight-forward diversification reactions from simple starting molecules. In this work this is exemplified by the biocatalytic synthesis of fifteen, so far undescribed, nucleoside analogues. Both sugar- and base modifications are accessible. This signifies a tremendous advantage over traditional chemical syntheses.","Nukleoside und ihre Analoga sind zentrale Moleküle in der modernen Krebstherapie und bei der Behandlung viraler Infektionen. Ihre effiziente Synthese ist jedoch chemisch anspruchsvoll. Dies führt zu langwierigen Syntheserouten und einer geringen Atomökonomie. Die Natur hingegen ist auf die, für Nukleoside typische, hohe Dichte an funktionellen Gruppen eingestellt. Nukleosidphosphorylasen sind für ihre hohe Regio- und Stereospezifität bekannt. Sie sind Teil des Nukleosidkatabolismus und führen die Nukleosidsynthese auf beeindruckend selektive Weise durch. Dies macht sie zu interessanten Enzymen für die Untersuchung des durch sie abgedeckten chemischen Raums. Das Potenzial thermophiler Nukleosidphosphorylasen ist in dieser Hinsicht besonders interessant, da sie sich durch hohe Stabilität unter extremen Bedingungen auszeichnen. Allerdings ist das Spektrum der enzymatisch zugänglichen Nukleosidanaloga noch wenig erforscht und die biokatalytische Nukleosidsynthese hat noch keine industrielle Relevanz erreicht. Kürzlich wurden die thermodynamischen Regeln dieser Reaktionen beschrieben, aber diese Erkenntnisse wurden noch nicht auf tatsächliche Synthesen angewendet. Ziel dieser Arbeit ist es, den Wert der Biokatalyse in der Nukleosidchemie zu verdeutlichen. Hierfür wurden die Enzyme in Reaktionen mit nicht-natürlichen Substraten eingesetzt und die Equilibriumskonstanten dieser Reaktionsansätze bestimmt. Das ermöglichte die Optimierung der Reaktionen hinsichtlich ihres Ausbeute-Abfall-Verhältnisses. Mit diesem Ansatz wurden di-halogenierte Purin-Nukleoside, 4‘-thio-Nukleoside, ein unerwartetes N7-Xanthosin sowie verschiedene Ribavirin Derivate in Milligramm-Ausbeuten hergestellt und gereinigt. Die Zytotoxizität in menschlichen Zelllinien wurde für ausgewählte Beispiele untersucht. Zusammenfassend wurde das eindrucksvolle Substratspektrum von thermophilen Nukleosidphosphorylasen bestätigt, welches die gerichtete Diversifizierung ausgehend von einfachen Startverbindungen ermöglicht. Dies wird durch die biokatalytische Synthese von fünfzehn, bisher unbeschriebenen, Nukleosidanaloga verdeutlicht. Auf diesem Wege wurden sowohl Zucker- als auch Basen-Modifikationen erhalten. Somit stellt dieser Ansatz einen erheblichen Vorteil gegenüber traditioneller chemischer Synthese dar."]},{"key":"dc:title","label":"Title","values":["Application of thermodynamic principles in biocatalytic synthesis of novel nucleoside analogues"]}]}],"canonical_facts":{"dc:contributor.advisor":["Neubauer, Peter"],"dc:creator":["Westarp, Sarah"],"dc:date.accessioned":["2025-04-15T13:48:15Z"],"dc:date.available":["2025-04-15T13:48:15Z"],"dc:date.issued":["2025"],"dc:description.abstract":["Nucleosides and analogues thereof are central molecules in modern cancer therapy and in the fight against viral infections. However, their efficient synthesis is a challenging task for synthetic chemistry. This necessitates lengthy routes and results in low atom economy. Nature’s chemistry set, on the other hand, is set up to work with the high density of functional groups of nucleosides. Nucleoside phosphorylases are known to be very regio- and stereospecific enzymes. They are part of the nucleoside salvage pathway and perform nucleoside synthesis in an impressively selective way. This makes them interesting enzymes to study concerning the chemical space they cover. In this regard, the potential of thermophilic nucleoside phosphorylases is especially intriguing due to their high stability under challenging conditions. However, the range of enzymatically accessible nucleoside analogues is underexplored and biocatalytic nucleoside synthesis has not yet reached industrial relevance. Recently, the thermodynamic rules of these reactions have been elucidated, but these findings have not been applied to actual reactions yet. This work aims to highlight the added value of biocatalytic approaches in nucleoside chemistry. To this end, the enzymes were challenged with non-natural substrates and the equilibrium constants of these reaction set-ups were determined. This made it possible to optimize reactions to obtain yield-wastebalanced processes. Using this approach, di-halogenated purine nucleosides, 4’-thionucleosides, an unexpected N7-xanthosine and various ribavirin derivates were synthesized and purified in milligram yields. The cytotoxicity in human cell lines was evaluated for selected examples. In conclusion, it is confirmed that thermophilic nucleoside phosphorylases exhibit an impressive substrate scope. This enables straight-forward diversification reactions from simple starting molecules. In this work this is exemplified by the biocatalytic synthesis of fifteen, so far undescribed, nucleoside analogues. Both sugar- and base modifications are accessible. This signifies a tremendous advantage over traditional chemical syntheses.","Nukleoside und ihre Analoga sind zentrale Moleküle in der modernen Krebstherapie und bei der Behandlung viraler Infektionen. Ihre effiziente Synthese ist jedoch chemisch anspruchsvoll. Dies führt zu langwierigen Syntheserouten und einer geringen Atomökonomie. Die Natur hingegen ist auf die, für Nukleoside typische, hohe Dichte an funktionellen Gruppen eingestellt. Nukleosidphosphorylasen sind für ihre hohe Regio- und Stereospezifität bekannt. Sie sind Teil des Nukleosidkatabolismus und führen die Nukleosidsynthese auf beeindruckend selektive Weise durch. Dies macht sie zu interessanten Enzymen für die Untersuchung des durch sie abgedeckten chemischen Raums. Das Potenzial thermophiler Nukleosidphosphorylasen ist in dieser Hinsicht besonders interessant, da sie sich durch hohe Stabilität unter extremen Bedingungen auszeichnen. Allerdings ist das Spektrum der enzymatisch zugänglichen Nukleosidanaloga noch wenig erforscht und die biokatalytische Nukleosidsynthese hat noch keine industrielle Relevanz erreicht. Kürzlich wurden die thermodynamischen Regeln dieser Reaktionen beschrieben, aber diese Erkenntnisse wurden noch nicht auf tatsächliche Synthesen angewendet. Ziel dieser Arbeit ist es, den Wert der Biokatalyse in der Nukleosidchemie zu verdeutlichen. Hierfür wurden die Enzyme in Reaktionen mit nicht-natürlichen Substraten eingesetzt und die Equilibriumskonstanten dieser Reaktionsansätze bestimmt. Das ermöglichte die Optimierung der Reaktionen hinsichtlich ihres Ausbeute-Abfall-Verhältnisses. Mit diesem Ansatz wurden di-halogenierte Purin-Nukleoside, 4‘-thio-Nukleoside, ein unerwartetes N7-Xanthosin sowie verschiedene Ribavirin Derivate in Milligramm-Ausbeuten hergestellt und gereinigt. Die Zytotoxizität in menschlichen Zelllinien wurde für ausgewählte Beispiele untersucht. Zusammenfassend wurde das eindrucksvolle Substratspektrum von thermophilen Nukleosidphosphorylasen bestätigt, welches die gerichtete Diversifizierung ausgehend von einfachen Startverbindungen ermöglicht. Dies wird durch die biokatalytische Synthese von fünfzehn, bisher unbeschriebenen, Nukleosidanaloga verdeutlicht. Auf diesem Wege wurden sowohl Zucker- als auch Basen-Modifikationen erhalten. Somit stellt dieser Ansatz einen erheblichen Vorteil gegenüber traditioneller chemischer Synthese dar."],"dc:identifier.uri":["https://depositonce.tu-berlin.de/handle/11303/24313","https://doi.org/10.14279/depositonce-23127"],"dc:language.iso":["en"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Application of thermodynamic principles in biocatalytic synthesis of novel nucleoside analogues"],"dc:type":["Doctoral Thesis"]},"updated_at":"2026-07-27T21:28:29Z"}