Photoreactive warheads for covalent fragment libraries

This project will be conducted within the Healthcare Technologies EPSRC theme and aligned with the research areas of Chemical Biology and Biological Chemistry, Chemical Reaction Dynamics and Mechanisms, and Synthetic Organic Chemistry.
The pharmaceutical pipeline requires the identification of effective tools for the dissection, interrogation and validation of new biological targets. Whilst photoreactive covalent fragment libraries provide an effective platform for the discovery of these tools in isolated proteins, their use in live cell environments is limited due to low levels of photo-crosslinking. We will address this shortfall by investigating the chemical reaction dynamics and mechanism of these warheads and define novel groups for the efficient and selective capture of proteins.
The specific target proteins to advance and showcase this warhead development will be the palmitoyl transferase zDHHC enzymes. This 23-member family are responsible for the acylation of cysteine residues, which influences the function, localisation and trafficking of substrate proteins. We will target the ligand binding domain of these proteins with the aim of providing tools to enable the identification of target substrates for each family member examined and develop a method to determine selectivity (if any) of novel compounds. This will require the identification of promiscuous probes, able to bind each zDHHC enzyme and to determine the level of labelling through mass spectrometry. This will represent the foundation of a simple and effective competitive binding assay to screen for new hit matter and establish selectivity profiles in a single experiment.
The development of each of these tools will provide a novel and powerful platform with which to investigate the zDHHC enzymes. In addition, the novel warheads will find application in the dissection and interrogation of alternative protein families of interest.