Tulane Virus Protease as a Structural Surrogate for Inhibitor Screening of Human Norovirus Proteases
Language
English
Publication Date
3-24-2026
Journal
Journal of Virology
DOI
10.1128/jvi.02176-25
PMID
41670373
PMCID
PMC13011392
PubMedCentral® Posted Date
2-11-2026
PubMedCentral® Full Text Version
Post-print
Abstract
Human norovirus (HuNoV) is a significant cause of gastroenteritis worldwide, affecting people of all age groups. There are currently no vaccines or drugs available, leaving susceptible populations vulnerable to severe or protracted illness. A HuNoV cultivation system is pivotal for screening norovirus antivirals. While the human intestinal enteroid cultivation system allows robust replication of multiple HuNoV strains, it presents technical and cost barriers. Tulane virus (TV), a surrogate for HuNoV, replicates well in monkey kidney cell lines and is closely related to norovirus in cellular biology. Here, we determined the structures of TV protease (TV-Pro) alone and in complex with rupintrivir, a picornavirus inhibitor that also inhibits HuNoV proteases (HuNoV-Pro). Our data validate TV as an efficient surrogate system for rapid screening of HuNoV protease inhibitors. The TV protease structure exhibits significant backbone similarity to the GI.1 HuNoV protease in the substrate-binding domain, with the BII-CII loop in an open conformation stabilized by hydrogen bonds as present in the GI.1 protease. Structural differences in the S2 pocket and two amino acid changes in the S4 pocket result in slightly altered P2 and P4 substrate and inhibitor conformations. Despite these differences, we confirm previous findings that the TV protease can cleave the GI.1 and GII HuNoV polyprotein substrates with high and moderate efficiency, respectively. We found that rupintrivir efficiently inhibits TV protease
Keywords
Humans, Peptide Hydrolases, Norovirus, Protease Inhibitors, Animals, Pyrrolidinones, Picornavirales, Antiviral Agents, Leucine, Caliciviridae, Models, Molecular, Protein Conformation, Viral Proteins, Drug Evaluation, Preclinical, Crystallography, X-Ray, Cell Line, Isoxazoles, Phenylalanine, Valine, noroviruses, proteases, protease inhibitors, crystal structures, inhibitor design, inhibition assays
Published Open-Access
yes
Recommended Citation
Pham, Son; Sharma, Nikhil; Sankaran, Banumathi; et al., "Tulane Virus Protease as a Structural Surrogate for Inhibitor Screening of Human Norovirus Proteases" (2026). Faculty, Staff and Students Publications. 6967.
https://digitalcommons.library.tmc.edu/baylor_docs/6967