Thair, Benjamin;
(2023)
Development of biocatalysts for the alkylation of complex molecules.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The medicinal effects of compounds can be dramatically improved by even the smallest alkylations of their structures. Making those additions selectively, however, can be challenging for traditional synthesis, especially when molecules have many reactive sites. This has limited the ability to access and study derivatives of complex molecules, which may be hampering the discovery of new bioactives. Methyltransferases (MTs) are a vast, structurally divergent class of enzymes, responsible for catalysing nearly all alkylation reactions in cells. In many cases, the transferral of a methyl group by an MT is highly selective, and able to significantly alter the interactions of the target. MTs thus have the potential to access the sought-after alkylated derivatives of medicinally promising structures. In doing so, they may allow the study and manufacture of molecules that would otherwise be difficult to produce. This thesis documents work towards the goal of realising that potential. A threeenzyme cascade was used to generate a reactive cofactor in situ, use that cofactor in MT reactions and break down the inhibitory side product. With this system, selective alkylation of compounds featuring the privileged tetrahydroisoquinoline scaffold were explored through small- and preparative-scale assays, with primary analysis by HPLC. The first efforts were towards methylation, comprising investigations using the more established biocatalyst catechol-O-MT alongside a search for novel MTs. The work then evolved into the development of capacity for other alkylations. Analogues of the alkyl donor methionine, sourced commercially and later through syntheses, were integrated into the cascades. The challenges encountered during this effort prompted computational investigations, directed mutagenesis to improve enzyme performance and ultimately a high-throughput random mutagenesis screen to search for improved enzyme variants.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Development of biocatalysts for the alkylation of complex molecules |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2023. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10168531 |
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