Understanding and Engineering the Biosynthesis of Thioamitide

Fong, King (2023) Understanding and Engineering the Biosynthesis of Thioamitide. Doctoral thesis, University of East Anglia.

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Ribosomally synthesised and post-translationally peptides (RiPPs) is a structurally diverse and clinically relevant class of natural products. The thioamitides, a RiPP family, have been drawing attention for their fascinating uncommon chemical features and promising antitumour activities. Moreover, their antitumour activities can vary with a single change of functional group.
With the rapidly developing bioinformatic tools and genome mining efforts, an increasing number of unusual and interesting biosynthetic pathways are being identified in bacteria, which is promising for the discovery of novel thioamitides with diverse molecular structures and consequently different biological activities. Here, thiopotensamide, a novel thioamitide produced by Nocardiopsis potens DSM 45234, is presented. This compound is characterised with a dehydration and an unexpected methylation that are not seen in other family members. Confirmation of the molecular structure by NMR was hampered by low productivity and the complexity of secondary metabolite production in the native producer host, as well as unsuccessful genetic manipulation of N. potens. However, heterologous expression of the biosynthetic gene cluster in a heterologous host provided promising results that enabled key insights into the biosynthesis of mature thiopotensamide.
In this thesis, the formation of thioamide bonds, one of the key chemical features from thioamitides, is also investigated using the biosynthetic pathway of thiostreptamide S4. This single atom substitution has been reported to play a key role in peptide stability and bioactivities elsewhere. It was hypothesised that the thioamide bond formation was catalysed by a YcaO-TfuA protein pair, which was investigated using in vitro biochemical reactions.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Kitty Laine
Date Deposited: 27 Jun 2023 13:16
Last Modified: 31 Dec 2023 01:38
URI: https://ueaeprints.uea.ac.uk/id/eprint/92517


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