Inhibiting a dynamic viral protease by targeting a non-catalytic cysteine

• Published in: Cell chemical biology Vol. 29; no. 5; pp. 785 - 798.e19
• Main Authors: Hulce, Kaitlin R., Jaishankar, Priyadarshini, Lee, Gregory M., Bohn, Markus-Frederik, Connelly, Emily J., Wucherer, Kristin, Ongpipattanakul, Chayanid, Volk, Regan F., Chuo, Shih-Wei, Arkin, Michelle R., Renslo, Adam R., Craik, Charles S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 19.05.2022
• Subjects: allostery; antiviral; conformational dynamics; covalent inhibitor; Cysteine; cytomegalovirus; Cytomegalovirus - physiology; Cytomegalovirus Infections; dimerization; herpesvirus; Humans; irreversible electrophile; non-catalytic cysteine; Peptide Hydrolases; protease; Viral Proteases; protease; non-catalytic cysteine; cytomegalovirus; conformational dynamics; herpesvirus; covalent inhibitor; antiviral; irreversible electrophile; dimerization; allostery
• ISSN: 2451-9456; 2451-9448; 2451-9456
• DOI: 10.1016/j.chembiol.2022.03.007

Viruses are responsible for some of the most deadly human diseases, yet available vaccines and antivirals address only a fraction of the potential viral human pathogens. Here, we provide a methodology for managing human herpesvirus (HHV) infection by covalently inactivating the HHV maturational protease via a conserved, non-catalytic cysteine (C161). Using human cytomegalovirus protease (HCMV Pr) as a model, we screened a library of disulfides to identify molecules that tether to C161 and inhibit proteolysis, then elaborated hits into irreversible HCMV Pr inhibitors that exhibit broad-spectrum inhibition of other HHV Pr homologs. We further developed an optimized tool compound targeted toward HCMV Pr and used an integrative structural biology and biochemical approach to demonstrate inhibitor stabilization of HCMV Pr homodimerization, exploiting a conformational equilibrium to block proteolysis. Irreversible HCMV Pr inhibition disrupts HCMV infectivity in cells, providing proof of principle for targeting proteolysis via a non-catalytic cysteine to manage viral infection. [Display omitted] •HHV proteases are inhibited by targeting a non-catalytic cysteine•Inhibitors bind the protease active site and engage the dimer interface•Protease inhibition stabilizes the inactivated homodimer•Inhibition disrupts HHV infectivity in cells Hulce et al. develop an irreversible inhibitor targeting a non-catalytic cysteine in human herpesvirus proteases. Inhibition leads to disrupted infectivity, validating irreversible protease inactivation as a method to manage herpes viral infection.