2fyq

Crystal Structure of the Norwalk Virus Protease

spinqualitylabelsall models 2fyq, resolution 1.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2fyq is a 1 chain structure with sequence from Norwalk calicivirus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL, PO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [POLG_NVN68] Protein p48 may play a role in viral replication by interacting with host VAPA, a vesicle-associated membrane protein that plays a role in SNARE-mediated vesicle fusion. This interaction may target replication complex to intracellular membranes. NTPase presumably plays a role in replication. Despite having similarities with helicases, does not seem to display any helicase activity. Protein P22 may play a role in targeting replication complex to intracellular membranes. Viral genome-linked protein is covalently linked to the 5'-end of the positive-strand, negative-strand genomic RNAs and subgenomic RNA. Acts as a genome-linked replication primer. May recruit ribosome to viral RNA thereby promoting viral proteins translation. 3C-like protease processes the polyprotein: 3CLpro-RdRp is first released by autocleavage, then all other proteins are cleaved. May cleave host polyadenylate-binding protein thereby inhibiting cellular translation (By similarity). RNA-directed RNA polymerase replicates genomic and antigenomic RNA by recognizing replications specific signals. Transcribes also a subgenomic mRNA by initiating RNA synthesis internally on antigenomic RNA. This sgRNA encodes for structural proteins. Catalyzes the covalent attachment VPg with viral RNAs (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Norwalk virus (NV), a member of the Caliciviridae family, is the major cause of acute, epidemic, viral gastroenteritis. The NV genome is a positive sense, single-stranded RNA that encodes three open reading frames (ORFs). The first ORF produces a polyprotein that is processed by the viral cysteine protease into six nonstructural proteins. We have determined the structure of the NV protease to 1.5 and 2.2 A from crystals grown in the absence or presence, respectively, of the protease inhibitor AEBSF [4-(2-aminoethyl)-benzenesulfonyl fluoride]. The protease, which crystallizes as a stable dimer, exhibits a two-domain structure similar to those of other viral cysteine proteases with a catalytic triad composed of His 30, Glu 54, and Cys 139. The native structure of the protease reveals strong hydrogen bond interactions between His 30 and Glu 54, in the favorable syn configuration, indicating a role of Glu 54 during proteolysis. Mutation of this residue to Ala abolished the protease activity, in a fluorogenic peptide substrate assay, further substantiating the role of Glu 54 during proteolysis. These observations contrast with the suggestion, from a previous study of another norovirus protease, that this residue may not have a prominent role in proteolysis (K. Nakamura, Y. Someya, T. Kumasaka, G. Ueno, M. Yamamoto, T. Sato, N. Takeda, T. Miyamura, and N. Tanaka, J. Virol. 79:13685-13693, 2005). In the structure from crystals grown in the presence of AEBSF, Glu 54 undergoes a conformational change leading to disruption of the hydrogen bond interactions with His 30. Since AEBSF was not apparent in the electron density map, it is possible that these conformational changes are due to subtle changes in pH caused by its addition during crystallization. X-ray crystallographic structure of the Norwalk virus protease at 1.5-A resolution.,Zeitler CE, Estes MK, Venkataram Prasad BV J Virol. 2006 May;80(10):5050-8. PMID:16641296 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Virus protease 3D structures

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