4hi3 | pdb_00004hi3

Crystal structure of dimeric R298A mutant of SARS coronavirus main protease

spinqualitylabelsall models 4hi3, resolution 2.09Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4hi3 is a 2 chain structure with sequence from Cvhsa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: 1a (CVHSA) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [R1A_CVHSA] The papain-like proteinase (PL-PRO) is responsible for the cleavages located at the N-terminus of replicase polyprotein. In addition, PL-PRO possesses a deubiquitinating/deISGylating activity and processes both 'Lys-48'- and 'Lys-63'-linked polyubiquitin chains from cellular substrates. Antagonizes innate immune induction of type I interferon by blocking the phosphorylation, dimerization and subsequent nuclear translocation of host IRF-3. The main proteinase 3CL-PRO is responsible for the majority of cleavages as it cleaves the C-terminus of replicase polyprotein at 11 sites. Recognizes substrates containing the core sequence [ILMVF]-Q-|-[SGACN]. Inhibited by the substrate-analog Cbz-Val-Asn-Ser-Thr-Leu-Gln-CMK (By similarity). Also contains an ADP-ribose-1-phosphate (ADRP)-binding function. Nsp7-nsp8 hexadecamer may possibly confer processivity to the polymerase, maybe by binding to dsRNA or by producing primers utilized by the latter. Nsp9 is a ssRNA-binding protein. Publication Abstract from PubMed The Severe acute respiratory syndrome coronavirus (SARS-CoV) main protease (M(pro)) cleaves two virion polyproteins (pp1a and pp1ab); this essential process represents an attractive target for the development of anti-SARS drugs. The functional unit of M(pro) is a homodimer and each subunit contains a His41/Cys145 catalytic dyad. Large amounts of biochemical and structural information are available on M(pro); nevertheless, the mechanism by which monomeric M(pro) is converted into a dimer during maturation still remains poorly understood. Previous studies have suggested that a C-terminal residue, Arg298, interacts with Ser123 of the other monomer in the dimer, and mutation of Arg298 results in a monomeric structure with a collapsed substrate-binding pocket. Interestingly, the R298A mutant of M(pro) shows a reversible substrate-induced dimerization that is essential for catalysis. Here, the conformational change that occurs during substrate-induced dimerization is delineated by X-ray crystallography. A dimer with a mutual orientation of the monomers that differs from that of the wild-type protease is present in the asymmetric unit. The presence of a complete substrate-binding pocket and oxyanion hole in both protomers suggests that they are both catalytically active, while the two domain IIIs show minor reorganization. This structural information offers valuable insights into the molecular mechanism associated with substrate-induced dimerization and has important implications with respect to the maturation of the enzyme. Mechanism for controlling the monomer-dimer conversion of SARS coronavirus main protease.,Wu CG, Cheng SC, Chen SC, Li JY, Fang YH, Chen YH, Chou CY Acta Crystallogr D Biol Crystallogr. 2013 May;69(Pt 5):747-55. doi:, 10.1107/S0907444913001315. Epub 2013 Apr 11. PMID:23633583 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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