9ZFN
Tulane virus protease without added ligands
Summary for 9ZFN
| Entry DOI | 10.2210/pdb9zfn/pdb |
| Descriptor | 3C-like protease (2 entities in total) |
| Functional Keywords | tulane virus protease, viral protein |
| Biological source | Tulane virus |
| Total number of polymer chains | 2 |
| Total formula weight | 36980.68 |
| Authors | |
| Primary citation | Pham, S.,Sharma, N.,Sankaran, B.,Nguyen, J.,Estes, M.K.,Hyser, J.M.,Prasad, B.V.V. Tulane virus protease as a structural surrogate for inhibitor screening of human norovirus proteases. J.Virol., :e0217625-e0217625, 2026 Cited by PubMed 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 and inhibits TV replication in cell culture with similar efficacy in combination with P-glycoprotein efflux pump inhibitors. We conclude that TV is a valuable surrogate for HuNoV protease inhibitor screening and outline strategies to improve its compatibility as such.IMPORTANCEHuman noroviruses (HuNoVs) are a significant cause of sporadic and epidemic gastroenteritis worldwide. There are no vaccines or antiviral drugs currently available to treat infections. Our work here demonstrates the potential of the Tulane virus cell culture system as a surrogate for screening small-molecule inhibitors of the human norovirus proteases. PubMed: 41670373DOI: 10.1128/jvi.02176-25 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.1 Å) |
Structure validation
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