Comparison of Enteroviral 3C Proteases, Which Ones Make the Cut?
Category: Research Poster
Author(s): Eliza Fuhs
Presenter(s): Eliza Fuhs
Mentors(s): Olve Peersen
Enteroviruses of the Picornaviridae family largely lack cures and primarily affect children often with fatal consequences. These positive sense ssRNA viruses utilize viral 3C proteases to cleave large polyproteins translated from the virus genome, specifically at Q:G junctions, into smaller functional proteins and interfere with host immune system proteins. I utilized fluorescence polarization assays to observe the interactions between 3C and polypeptide cleavage junctions through protein purification and design of native and mutant 14 nucleotide fluorescently labeled peptides. I found that the 3Cs of four picornaviruses had different enzymatic efficiency and cleavage specificity patterns. Poliovirus 3C and Human Rhino Virus - B14 3C were generally the most enzymatically efficient, and the most efficient enzyme peptide combination was this HRV-B14 3C on the 2C:3A junction. All four enzymes were found to have the greatest specificity for junction 2C:3A followed by 3B:3C while being relatively nonspecific for the other three junctions. Single point mutations in peptides with HRV-B14 3C revealed two nucleotide identities N-terminal to the Q:G junction that were key determinants of protease cleavage specificity with the junction. These findings provide context on picornaviral 3C function and biochemistry that may increase potential for the creation of multi-viral inhibitors.