Exploitation of enzyme promiscuity to generate ribosomal natural product diversity

Natural sources have been highly important for the discovery of new drugs, offering compounds that possess exciting and potent bioactivities.

The development of many promising natural products is significantly hampered by the difficulties associated with the synthesis of novel analogs.

The family of ribosomally synthesized and post-translationally modified peptide (RiPP) natural products offers a plethora of different, promising bioactivities and highly diverse scaffolds.

I propose to develop two new complementary routes to generate modified, bespoke RiPPs in vitro and in vivo: Interchangeable leader peptide (ILP) technology, which is a novel approach tailored to RiPPs.

Every RiPP is produced from a precursor peptide that consists of a core peptide (the eventual natural product) and a pathway-specific recognition sequence that is recognized by parts of the biosynthetic machinery.

ILP technology will allow me to swap out recognition sequences and thus combine the biosynthetic machineries from diverse RiPP pathways in a mix-and-match approach to generate new-to-nature, hybrid RiPPs using two routes: (1) We will develop this technology in vitro to take full advantage of non-natural amino acids and other building blocks. (2) We will transfer an optimized, streamlined version to an in vivo setting using peptide ligation in the cytoplasm of E. coli.

This will allow us to use the power of genetics to create large libraries of compounds.

I will harvest the novel enzymatic modifications enabled by ILPs to generate diverse RiPP scaffolds that contain amino acids, non-natural amino acids, enzymatically modified amino acids and non-a-amino acid building blocks. We will then use ILP technology to identify novel pathoblockers for Pseudomonas aeruginosa.

The successful completion of this project will revolutionize the design of RiPPs-inspired next generation libraries with diverse scaffolds for application in tool compound development, target identification and drug discovery.