WEHI Wednesday Seminar hosted by Melissa & Matt Call
 

Xinyu Wu
PhD Student – Call Laboratory, Structural Biology division – New Medicines & Advanced Technologies Theme, WEHI (this is a PhD Completion seminar)
 

Mutational profiling of SARS-CoV-2 Papain-Like protease reveals requirements for function, structure, and drug escape

 

Davis Auditorium

Join via SLIDO enter code #WEHIWednesday

Including Q&A session
 

I embarked on my PhD studies one year later than planned due to border closures during the COVID-19 pandemic. At the time, COVID-19 felt like a disruption to my future career, but when my supervisors asked if I wanted to work on a COVID-related project, I jumped at the chance turning a barrier into an opportunity. 
 
In this seminar, I will present work recently published in Nature Communications and ongoing work to determine drug-escape variants to next generation treatments for COVID-19.
 
Coronaviruses like SARS-CoV-2, the causative agent of COVID-19, rely on two proteases to support their replication: Main protease (Mpro) and Papain-Like protease (PLpro). The former has been exploited as the main target of Nirmatrelvir, a protease inhibitor for COVID-19 treatment. Targeting PLpro may offer additional benefits, as it also removes protein modifications, including Interferon Stimulated Gene 15 (ISG15), that play a role in innate immunity against viruses. To thoroughly characterise this promising drug target, I analysed the sequence-function landscape of SARS-CoV-2 PLpro and explored potential drug escape pathways using an advanced saturation mutagenesis approach known as Deep Mutational Scanning (DMS). This approach characterises the function and abudance of ~6300 single-site substituted PLpro variants, in a library format comprising over 200,000 barcoded DNA variants. Using this data, I identified a connected network of amino acids affecting PLpro activity that extends far from the active site and substrate binding pocket, providing new insights into the PLpro cleavage mechanism. Adapting these screens, I can predict drug escape variants against emerging inhibitors from the literature, published patents and through our own drug development pipeline to determine the pathways to drug escape. This work demonstrates the power of DMS to elucidate the structure-function relationship of viral proteases and to inform the design of effective and robust antiviral drugs.
 

All welcome!