Cysteine proteases use a catalytic triad to help facilitate the hydrolysis reaction. This catalytic triad consists of three amino acids in the active site: Cys, His, and Asp. Using the structure of the cysteine protease, with the bound inhibitor (pdb 5R84), locate the active site, the inhibitor, and the three proposed catalytic residues (Cys, His, and Asp) in the active site. In your image, be sure to label the inhibitor and the three residues.
Cysteine Protease (from SARS-CoV-2) with non-covalent inhibitor bound — pdb id 5R84