Biophysical and Structural Characterization of Peptide Macrocycle-based Huntingtin Degraders

Huntington’s Disease (HD) is a debilitating neurodegenerative disease marked by progressive loss of motor control and cognitive function. Presently, there are no disease-modifying therapies. A potential avenue for slowing or stopping HD progression is to target huntingtin (HTT), or polyglutamine-expanded mutant HTT (mHTT), for degradation using proteasome targeting chimera (PROTAC) technology. A PROTAC will bring HTT and an E3 ligase into close proximity so that the E3 ligase can ubiquitinate HTT, serving as a degradation signal in the cell.
An ongoing collaboration between the labs of Rachel Harding and Hiroaki Suga has yielded a collection of HTT-targeting macrocyclic peptides (MPs). MPs offer the combined benefits of antibody-like specificity and small molecule-like cell permeability and stability. On the other hand, conveniently, the Structural Genomics Consortium has recently discovered a micromolar affinity ligand for TRIM7, an E3 ligase expressed in the brain.
To develop HTT-TRIM7 PROTACs, they will first be modeled in silico for optimal linker length and composition and then synthesized in collaboration with SGC. Next, PROTAC functionality and specificity will be validated by monitoring degradation of HTT in the cell. Finally, the HTT-PROTAC-TRIM7 complex will be visualized and corroborated using Cryogenic Electron Microscopy (Cryo-EM) and Hydrogen-Deuterium Exchange Mass Spectrometry (HDX-MS).
Consistent with Dr. Harding’s and the SGC’s commitment to open science, all work will be shared openly and contribute to the knowledge base of precompetitive, preclinical science. Together, we will take steps toward HD-modifying therapeutic interventions.

Faculty Supervisor:

Rachel Harding

Student:

Partner:

Structural Genomics Consortium

Discipline:

Life Sciences

Sector:

Professional, scientific and technical services

University:

University of Toronto

Program: