6B6I:
reference: Structural and antiviral studies of the human norovirus GII.4 protease., Muzzarelli KM, Kuiper BD, Spellmon N, Brunzelle JS, Hackett J, Amblard F, Zhou S, Liu P, Kovari IA, Yang Z, Schinazi RF, Kovari LC, Biochemistry. 2019 Jan 3. doi: 10.1021/acs.biochem.8b01063. PMID: 30605321

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