Oral Presentation 25th Annual Lorne Proteomics Symposium 2020

Comprehensive Quantitative Stability Assay (CQSA) system for defining the molecular resolution of protein-compound interactions in Mycobacterium tuberculosis. (#85)

Robert L Moritz 1
  1. Institute For Systems Biology, Seattle, WA, United States

Tuberculosis is an old but re-emerging global health threat caused by mycobacteria belonging to the Mycobacterium tuberculosis family. With 1/3 (~2.5-billion) of the world’s population infected with Mtb and at least 9M new cases, resulting in 1.7M deaths annually, Mtb is by far the largest burden of disease and a global health emergency affecting not only the developing world. Exacerbating this epidemic is the threat of increasing multidrug-resistant tuberculosis (MDR-TB) which will ultimately cause a further increase of TB cases amongst areas of the population currently unaffected creating a massive social impact. In more than over 50-years of research, Bedaquiline, is the only approved fast-tracked antibiotic, despite its severe complications, for the treatment of MDR-TB. These complications include nausea, arthralgias, hemoptysis, hyperuricemia, rash, extremity- and chest-pain, cardiac-QTc prolongation and more striking - unilateral-deafness. The ability to identify early-stage compounds with a better understanding of action at the molecular level rapidly provides information to drug development programs that can ultimately benefit patients in poor resource settings the most.

Alterations in physicochemical properties of proteins in cells, lysates, organelles, and living organisms by deliberate stability modulation probed by comprehensive-quantitative proteome-wide scale measurements is such a tool that can greatly inform direct actions of molecules and positively define intended targets and possible off-targets in an unbiased format. We have developed the Comprehensive-Quantitative-Stability-Assay (CQSA) system that is a state-of-the-art, high-throughput proteomics method combining power, speed and molecular resolution to screen proteomes such as pathogens and their human hosts for protein-compound interactions over a wide range. We have used the CQSA system to specifically identify protein interactions with long-term known drugs in TB therapy and with promising lead compounds in TB drug development pipelines to provide information that will assist in the decision making of compound progression or its halt in drug development. The CQSA-system has confirmed target-protein engagement with high-specificity and has identified novel off-target effects where we have definitive x-ray crystallography structural data characterizing the binding and elucidating hitherto pleiotropy of these compounds.