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Substrate specificity of Tulane virus protease
Chao Wei1, Jarek Meller, Xi Jiang
1Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
Abstract:
Tulane virus (TV) is a cultivable calicivirus isolated from rhesus monkeys. In this study, we characterized the substrate specificity of TV protease in trans using recombinant proteases and TV polyprotein fragments containing the predicted proteolytic cleavage sites. Cleavage products have been obtained from 4 of the 5 fragments containing (573)Q-S(574) between the helicase and 3A-like protein, (712)E-A(713) between the 3A-like protein and Vpg, (802)E-G(803) between Vpg and the protease, and (976)E-G(977) between the protease and RdRp. We also characterized the enzymatic activities of the recombinant proteases of TV and Norwalk virus using synthetic fluorogenic peptide substrates. Under optimal conditions for enzymatic assays, partial cross-reactivities on reciprocal substrates were observed between TV and Norwalk virus proteases. The apparently shared substrate specificities between TV and Norwalk virus proteases suggested that the cultivable TV could be used as a model for in vivo evaluation of lead candidates of protease inhibitors for human norovirus.
Insights
Tulane virus protease exhibits substrate specificities similar to Norwalk virus protease. This suggests Tulane virus can serve as a model for developing human norovirus protease inhibitors.
Area of Science:
- Virology
- Molecular Biology
Background:
- Tulane virus (TV) is a calicivirus found in rhesus monkeys.
- Understanding TV protease function is crucial for developing antiviral strategies.
Purpose of the Study:
- To characterize the substrate specificity of Tulane virus protease.
- To compare TV protease activity with Norwalk virus protease.
Main Methods:
- Used recombinant proteases and polyprotein fragments of TV.
- Analyzed cleavage sites within the TV polyprotein.
- Assessed enzymatic activities using synthetic fluorogenic peptide substrates.
Main Results:
- Identified TV protease cleavage sites between helicase/3A-like protein, 3A-like protein/Vpg, Vpg/protease, and protease/RdRp.
- Observed partial cross-reactivity between TV and Norwalk virus proteases on reciprocal substrates.
Conclusions:
- Tulane virus protease shares substrate specificities with Norwalk virus protease.
- Cultivable Tulane virus can be a valuable model for evaluating human norovirus protease inhibitors in vivo.
