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dc.contributor.advisorHulme, Alison
dc.contributor.advisorDuncan, Rory
dc.contributor.authorAllan, Christopher
dc.date.accessioned2018-09-04T11:02:48Z
dc.date.available2018-09-04T11:02:48Z
dc.date.issued2018-11-29
dc.identifier.urihttp://hdl.handle.net/1842/31547
dc.description.abstractProtein modification is an essential tool in Chemical Biology, allowing a functional biomolecule to be equipped with a small molecule tag or label. However, as proteins are constructed from a limited palette of around 20 canonical amino acids, achieving selective modification can be problematic. Previously reported methods for protein modification will be discussed in Chapter 1; these often rely on alteration of the protein sequence to introduce a uniquely reactive (often non-canonical) amino acid which may then be covalently modified in a bioorthogonal manner. An alternative approach is to identify a uniquely reactive site within the native protein sequence, such as the protein N-terminus or the reactive side chain of an amino acid with low frequency, and modify this using selective chemistry. In this project, modification of a native sequence protein was achieved by targeting a low abundance residue, tyrosine (Tyr), in a selective manner. Tyr was identified as the ideal candidate as it displays only ~3% frequency in the proteome and, due to its electron-rich aryl ring, it can be selectively modified by electrophilic aromatic substitution. Using a diazonium salt as the tuned electrophile, modification results in formation of an azobenzene motif which may be orthogonally cleaved under mild reducing conditions. The resulting cleavage product bears an o-aminophenol modification on the Tyr side chain, which can then be conjugated to a fluorescent label using established chemistry. This system has been developed on a solid-phase platform to give further control over the extent of modification achieved. In Chapter 2, the component parts of this method are developed through reactions performed in-solution on small molecule substrates. In Chapter 3, this work is then moved onto a solid-phase resin in order to ‘catch-and-release’ small molecule and peptide substrates. Finally in Chapter 4, the resin-based catch-and-release system is optimised for use in protein modification, and analysis of the modification site is explored.en
dc.contributor.sponsorEngineering and Physical Sciences Research Council (EPSRC)en
dc.language.isoenen
dc.publisherThe University of Edinburghen
dc.subjectproteinsen
dc.subjectprotein labellingen
dc.subjecttyrosineen
dc.subjectsolid-phase resinen
dc.titleTargeting tyrosine: a catch-and-release approach to protein modificationen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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