Non-ribosomal peptide synthetases (NRPSs) have been studied for over 40 years due to the significance of their bioactive natural products, as well as their complex and impressive biosynthetic machinery. Unfortunately, the structural complexity of NPcPs has hindered chemical and biochemical efforts to synthesize analogues for drug discovery. Non-ribosomal cyclic peptides are a major class of NPcPs, they are assembled by modular mega enzymes known as non-ribosomal peptide synthetases (NRPS). Each module is responsible for sequentially adding a new amino acid to the covalently bound linear peptide. This sequential order is pre-defined by evolution. Then, the mature cyclic precursor is prominently released via macrocyclization by C-terminal thioesterase (TE domain) in vivo. My PhD work firstly describes the use of synthetic linear peptide library to investigate the role of RufT TE domain in enzymatic cyclization in vitro (Chapter 2). Furthermore, it describes the development of a super rapid chemical macrocyclization strategy, operationally simple and high yielding. The super-fast macrocyclisation rate provides insight into the structural logic encoded in NRPS linear enzymatic assembly lines. This reveals that the order of modules promotes formation of a linear peptide which is pre-organised for cyclisation (Chapter 3). Additionally, this fast cyclisation was applied to other NPcPs comprising various cyclisation styles (Chapter 4). In conclusion, this work will aid future efforts to engineer NRPS biosynthetic pathways and facilitate the synthesis of derivative libraries of bioactive NPcPs for medicinal chemistry study.
Advancing Synthetic Strategies for Non-Ribosomal Cyclic Peptides: An Exploration of Facile Methodologies in Macrocyclisation
Ding, Y. (Author). 1 Nov 2024
Student thesis: Doctoral Thesis › Doctor of Philosophy