View source for 2bx4


==Crystal Structure of SARS Coronavirus Main Proteinase (P21212)==
<StructureSection load='2bx4' size='340' side='right'caption='[[2bx4]], [[Resolution|resolution]] 2.79&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2bx4]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/SARS_coronavirus_Sin2774 SARS coronavirus Sin2774]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2BX4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2BX4 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.79&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2bx4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2bx4 OCA], [https://pdbe.org/2bx4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2bx4 RCSB], [https://www.ebi.ac.uk/pdbsum/2bx4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2bx4 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/R1AB_SARS R1AB_SARS] Multifunctional protein involved in the transcription and replication of viral RNAs. Contains the proteinases responsible for the cleavages of the polyprotein.  Inhibits host translation by interacting with the 40S ribosomal subunit. The nsp1-40S ribosome complex further induces an endonucleolytic cleavage near the 5'UTR of host mRNAs, targeting them for degradation. Viral mRNAs are not susceptible to nsp1-mediated endonucleolytic RNA cleavage thanks to the presence of a 5'-end leader sequence and are therefore protected from degradation. By suppressing host gene expression, nsp1 facilitates efficient viral gene expression in infected cells and evasion from host immune response (PubMed:23035226). May disrupt nuclear pore function by binding and displacing host NUP93 (PubMed:30943371).<ref>PMID:23035226</ref> <ref>PMID:30943371</ref>   May play a role in the modulation of host cell survival signaling pathway by interacting with host PHB and PHB2. Indeed, these two proteins play a role in maintaining the functional integrity of the mitochondria and protecting cells from various stresses.<ref>PMID:19640993</ref>   Responsible for the cleavages located at the N-terminus of the 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 (PubMed:17692280). Plays a role in host membrane rearrangement that leads to creation of cytoplasmic double-membrane vesicles (DMV) necessary for viral replication. Nsp3, nsp4 and nsp6 together are sufficient to form DMV (PubMed:24410069). Antagonizes innate immune induction of type I interferon by blocking the phosphorylation, dimerization and subsequent nuclear translocation of host IRF3 (PubMed:19369340, PubMed:24622840). Prevents also host NF-kappa-B signaling.<ref>PMID:16271890</ref> <ref>PMID:17692280</ref> <ref>PMID:19369340</ref> <ref>PMID:24622840</ref> <ref>PMID:24410069</ref>   Plays a role in host membrane rearrangement that leads to creation of cytoplasmic double-membrane vesicles (DMV) necessary for viral replication. Alone appears incapable to induce membrane curvature, but together with nsp3 is able to induce paired membranes. Nsp3, nsp4 and nsp6 together are sufficient to form DMV.<ref>PMID:23943763</ref> <ref>PMID:24410069</ref>   Cleaves the C-terminus of replicase polyprotein at 11 sites. Recognizes substrates containing the core sequence [ILMVF]-Q-|-[SGACN]. Also able to bind an ADP-ribose-1''-phosphate (ADRP). May cleave host ATP6V1G1 thereby modifying host vacuoles intracellular pH.[PROSITE-ProRule:PRU00772]<ref>PMID:16226257</ref>   Plays a role in host membrane rearrangement that leads to creation of cytoplasmic double-membrane vesicles (DMV) necessary for viral replication. Nsp3, nsp4 and nsp6 together are sufficient to form DMV (PubMed:24410069). Plays a role in the initial induction of autophagosomes from host reticulum endoplasmic. Later, limits the expansion of these phagosomes that are no longer able to deliver viral components to lysosomes (PubMed:24991833).<ref>PMID:24991833</ref> <ref>PMID:24410069</ref>   Forms a hexadecamer with nsp8 (8 subunits of each) that may participate in viral replication by acting as a primase. Alternatively, may synthesize substantially longer products than oligonucleotide primers.<ref>PMID:22039154</ref>   Forms a hexadecamer with nsp7 (8 subunits of each) that may participate in viral replication by acting as a primase. Alternatively, may synthesize substantially longer products than oligonucleotide primers.<ref>PMID:22039154</ref>   May participate in viral replication by acting as a ssRNA-binding protein.<ref>PMID:19153232</ref>   Plays a pivotal role in viral transcription by stimulating both nsp14 3'-5' exoribonuclease and nsp16 2'-O-methyltransferase activities. Therefore plays an essential role in viral mRNAs cap methylation.<ref>PMID:22635272</ref>   Responsible for replication and transcription of the viral RNA genome.<ref>PMID:22791111</ref>   Multi-functional protein with a zinc-binding domain in N-terminus displaying RNA and DNA duplex-unwinding activities with 5' to 3' polarity. Activity of helicase is dependent on magnesium.<ref>PMID:12917423</ref> <ref>PMID:22615777</ref>   Enzyme possessing two different activities: an exoribonuclease activity acting on both ssRNA and dsRNA in a 3' to 5' direction and a N7-guanine methyltransferase activity (PubMed:16549795, PubMed:20421945, PubMed:22635272). Acts as a proofreading exoribonuclease for RNA replication, thereby lowering The sensitivity of the virus to RNA mutagens (PubMed:23966862, PubMed:29511076, PubMed:21593585).<ref>PMID:16549795</ref> <ref>PMID:20421945</ref> <ref>PMID:21593585</ref> <ref>PMID:22635272</ref> <ref>PMID:23966862</ref> <ref>PMID:29511076</ref>   Mn(2+)-dependent, uridylate-specific enzyme, which leaves 2'-3'-cyclic phosphates 5' to the cleaved bond.  Methyltransferase that mediates mRNA cap 2'-O-ribose methylation to the 5'-cap structure of viral mRNAs. N7-methyl guanosine cap is a prerequisite for binding of nsp16. Therefore plays an essential role in viral mRNAs cap methylation which is essential to evade immune system.<ref>PMID:18417574</ref> <ref>PMID:20421945</ref> 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/bx/2bx4_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2bx4 ConSurf].
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== Publication Abstract from PubMed ==
The SARS coronavirus main proteinase (M(pro)) is a key enzyme in the processing of the viral polyproteins and thus an attractive target for the discovery of drugs directed against SARS. The enzyme has been shown by X-ray crystallography to undergo significant pH-dependent conformational changes. Here, we assess the conformational flexibility of the M(pro) by analysis of multiple crystal structures (including two new crystal forms) and by molecular dynamics (MD) calculations. The MD simulations take into account the different protonation states of two histidine residues in the substrate-binding site and explain the pH-activity profile of the enzyme. The low enzymatic activity of the M(pro) monomer and the need for dimerization are also discussed.

pH-dependent conformational flexibility of the SARS-CoV main proteinase (M(pro)) dimer: molecular dynamics simulations and multiple X-ray structure analyses.,Tan J, Verschueren KH, Anand K, Shen J, Yang M, Xu Y, Rao Z, Bigalke J, Heisen B, Mesters JR, Chen K, Shen X, Jiang H, Hilgenfeld R J Mol Biol. 2005 Nov 18;354(1):25-40. Epub 2005 Sep 23. PMID:16242152<ref>PMID:16242152</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2bx4" style="background-color:#fffaf0;"></div>

==See Also==
*[[Virus protease 3D structures|Virus protease 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: SARS coronavirus Sin2774]]
[[Category: Bigalke J]]
[[Category: Hilgenfeld R]]
[[Category: Mesters JR]]
[[Category: Verschueren KHG]]