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|  | <table><tr><td colspan='2'>[[7rvs]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome_coronavirus_2 Severe acute respiratory syndrome coronavirus 2]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7RVS OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7RVS FirstGlance]. <br> |  | <table><tr><td colspan='2'>[[7rvs]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome_coronavirus_2 Severe acute respiratory syndrome coronavirus 2]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7RVS OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7RVS 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]] 1.85Å</td></tr> |  | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.85Å</td></tr> | 
| - | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=81L:N-[(benzyloxy)carbonyl]-3-methyl-L-valyl-3-cyclopropyl-N-{(2S)-1-hydroxy-3-[(3S)-2-oxopyrrolidin-3-yl]propan-2-yl}-L-alaninamide'>81L</scene>, <scene name='pdbligand=CSO:S-HYDROXYCYSTEINE'>CSO</scene></td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=81L:(phenylmethyl)+~{N}-[(2~{S})-1-[[(2~{S})-3-cyclopropyl-1-oxidanylidene-1-[[(2~{S})-1-oxidanyl-3-[(3~{S})-2-oxidanylidenepyrrolidin-3-yl]propan-2-yl]amino]propan-2-yl]amino]-3,3-dimethyl-1-oxidanylidene-butan-2-yl]carbamate'>81L</scene>, <scene name='pdbligand=CSO:S-HYDROXYCYSTEINE'>CSO</scene></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=7rvs FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7rvs OCA], [https://pdbe.org/7rvs PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7rvs RCSB], [https://www.ebi.ac.uk/pdbsum/7rvs PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7rvs ProSAT]</span></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=7rvs FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7rvs OCA], [https://pdbe.org/7rvs PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7rvs RCSB], [https://www.ebi.ac.uk/pdbsum/7rvs PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7rvs ProSAT]</span></td></tr> | 
|  | </table> |  | </table> | 
| - | == Function == | + | <div style="background-color:#fffaf0;"> | 
| - | [https://www.uniprot.org/uniprot/R1AB_SARS2 R1AB_SARS2] Multifunctional protein involved in the transcription and replication ofviral RNAs. Contains theproteinases responsible for the cleavages of the polyprotein.[UniProtKB:P0C6X7]  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 fordegradation. Viral mRNAs are not susceptible to nsp1-mediated endonucleolytic RNA cleavage thanks to thepresence ofa 5'-end leader sequence and are therefore protected from degradation. Bysuppressing host gene expression, nsp1 facilitates efficient viral gene expression in infected cells andevasion from host immune response.[UniProtKB:P0C6X7]  May play a role in the modulation of host cell survival signaling pathway by interacting with host PHB andPHB2. Indeed, these two proteins play a role in maintaining the functional integrity of the mitochondria and protecting cells from various stresses.[UniProtKB:P0C6X7]  Responsible for the cleavages located at the N-terminus of the replicase polyprotein. In addition,PL-PRO possesses a deubiquitinating/deISGylating activity andprocesses both 'Lys-48'-and 'Lys-63'-linked polyubiquitin chains from cellular substrates. Participates together with nsp4 in the assembly of virally-induced cytoplasmic double-membrane vesicles necessary for viral replication.Antagonizes innate immune induction oftype I interferon by blocking the phosphorylation,dimerization and subsequent nuclear translocation ofhost IRF3. Prevents also host NF-kappa-B signaling.[UniProtKB:P0C6X7]  Participates inthe assembly of virally-induced cytoplasmic double-membrane vesicles necessary for viral replication.[UniProtKB:P0C6X7]  Cleaves the C-terminus ofreplicase polyprotein at 11 sites.Recognizes substrates containing the core sequence [ILMVF]-Q-|-[SGACN] (PubMed:32198291).Also able tobind an ADP-ribose-1''-phosphate (ADRP).[UniProtKB:P0C6X7]<ref>PMID:32198291</ref>   Plays a role in theinitial induction ofautophagosomes from host reticulum endoplasmic.Later,limits theexpansion ofthese phagosomes that are no longer able todeliver viral components to lysosomes.[UniProtKB:P0C6X7]  Forms a hexadecamer with nsp8 (8 subunits of each)that may participate inviral replication by acting as a primase. Alternatively,may synthesize substantially longer products than oligonucleotide primers.[UniProtKB:P0C6X7]  Forms a hexadecamer with nsp7 (8 subunits of each) thatmay participate inviral replication by acting as a primase.Alternatively, may synthesize substantially longer products than oligonucleotide primers.[UniProtKB:P0C6X7]  May participate inviral replication by acting as a ssRNA-binding protein.[UniProtKB:P0C6X7]  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.[UniProtKB:P0C6X7]  Responsible for replication andtranscription of the viral RNA genome.[UniProtKB:P0C6X7]  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 isdependent on magnesium.[UniProtKB:P0C6X7]  Enzyme possessing two different activities: an exoribonuclease activity acting on both ssRNA and dsRNA in a3' to5' direction anda N7-guanine methyltransferase activity. Acts as a proofreading exoribonuclease forRNA replication, thereby lowering The sensitivity ofthe virus to RNA mutagens.[UniProtKB:P0C6X7]  Mn(2+)-dependent, uridylate-specific enzyme, which leaves 2'-3'-cyclic phosphates 5' to the cleaved bond.[UniProtKB:P0C6X7]  Methyltransferase that mediates mRNA cap 2'-O-ribose methylation to the 5'-cap structure of viral mRNAs.N7-methyl guanosine cap is aprerequisite for binding ofnsp16.Therefore plays an essential role in viral mRNAs cap methylation which is essential to evade immune system.[UniProtKB:P0C6X7]
 | + | == Publication Abstract from PubMed == | 
|  | + | As an essential enzyme of SARS-CoV-2, the COVID-19 pathogen, main protease (M(Pro)) is a viable target to develop antivirals for the treatment of COVID-19. By varying chemical compositions at both P2 and P3 positions and the N-terminal protection group, we synthesized 18 tripeptidyl M(Pro) inhibitors that contained also an aldehyde warhead and beta-(S-2-oxopyrrolidin-3-yl)-alaninal at the P1 position. Systematic characterizations of these inhibitors were conducted, including their in vitro enzymatic inhibition potency, X-ray crystal structures of their complexes with M(Pro), their inhibition of M(Pro) transiently expressed in 293T cells, and cellular toxicity and SARS-CoV-2 antiviral potency of selected inhibitors. These inhibitors have a large variation of determined in vitro enzymatic inhibition IC(50) values that range from 4.8 to 650 nM. The determined in vitro enzymatic inhibition IC(50) values reveal that relatively small side chains at both P2 and P3 positions are favorable for achieving high in vitro M(Pro) inhibition potency, the P3 position is tolerable toward unnatural amino acids with two alkyl substituents on the alpha-carbon, and the inhibition potency is sensitive toward the N-terminal protection group. X-ray crystal structures of M(Pro) bound with 16 inhibitors were determined. In all structures, the M(Pro) active site cysteine interacts covalently with the aldehyde warhead of the bound inhibitor to form a hemithioacetal that takes an S configuration. For all inhibitors, election density around the N-terminal protection group is weak indicating possible flexible binding of this group to M(Pro). In M(Pro), large structural variations were observed on residues N142 and Q189. Unlike their high in vitro enzymatic inhibition potency, most inhibitors showed low potency to inhibit M(Pro) that was transiently expressed in 293T cells. Inhibitors that showed high potency to inhibit M(Pro) transiently expressed in 293T cells all contain O-tert-butyl-threonine at the P3 position. These inhibitors also exhibited relatively low cytotoxicity and high antiviral potency. Overall, our current and previous studies indicate that O-tert-butyl-threonine at the P3 site is a key component to achieve high cellular and antiviral potency for tripeptidyl aldehyde inhibitors of M(Pro). | 
|  | + |   | 
|  | + | A multi-pronged evaluation of aldehyde-based tripeptidyl main protease inhibitors as SARS-CoV-2 antivirals.,Ma Y, Yang KS, Geng ZZ, Alugubelli YR, Shaabani N, Vatansever EC, Ma XR, Cho CC, Khatua K, Xiao J, Blankenship LR, Yu G, Sankaran B, Li P, Allen R, Ji H, Xu S, Liu WR Eur J Med Chem. 2022 Oct 5;240:114570. doi: 10.1016/j.ejmech.2022.114570. Epub , 2022 Jun 27. PMID:35779291<ref>PMID:35779291</ref> | 
|  | + |   | 
|  | + | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | 
|  | + | </div> | 
|  | + | <div class="pdbe-citations 7rvs" style="background-color:#fffaf0;"></div> | 
|  | == References == |  | == References == | 
|  | <references/> |  | <references/> | 
|  |   Structural highlights 
  Publication Abstract from PubMed As an essential enzyme of SARS-CoV-2, the COVID-19 pathogen, main protease (M(Pro)) is a viable target to develop antivirals for the treatment of COVID-19. By varying chemical compositions at both P2 and P3 positions and the N-terminal protection group, we synthesized 18 tripeptidyl M(Pro) inhibitors that contained also an aldehyde warhead and beta-(S-2-oxopyrrolidin-3-yl)-alaninal at the P1 position. Systematic characterizations of these inhibitors were conducted, including their in vitro enzymatic inhibition potency, X-ray crystal structures of their complexes with M(Pro), their inhibition of M(Pro) transiently expressed in 293T cells, and cellular toxicity and SARS-CoV-2 antiviral potency of selected inhibitors. These inhibitors have a large variation of determined in vitro enzymatic inhibition IC(50) values that range from 4.8 to 650 nM. The determined in vitro enzymatic inhibition IC(50) values reveal that relatively small side chains at both P2 and P3 positions are favorable for achieving high in vitro M(Pro) inhibition potency, the P3 position is tolerable toward unnatural amino acids with two alkyl substituents on the alpha-carbon, and the inhibition potency is sensitive toward the N-terminal protection group. X-ray crystal structures of M(Pro) bound with 16 inhibitors were determined. In all structures, the M(Pro) active site cysteine interacts covalently with the aldehyde warhead of the bound inhibitor to form a hemithioacetal that takes an S configuration. For all inhibitors, election density around the N-terminal protection group is weak indicating possible flexible binding of this group to M(Pro). In M(Pro), large structural variations were observed on residues N142 and Q189. Unlike their high in vitro enzymatic inhibition potency, most inhibitors showed low potency to inhibit M(Pro) that was transiently expressed in 293T cells. Inhibitors that showed high potency to inhibit M(Pro) transiently expressed in 293T cells all contain O-tert-butyl-threonine at the P3 position. These inhibitors also exhibited relatively low cytotoxicity and high antiviral potency. Overall, our current and previous studies indicate that O-tert-butyl-threonine at the P3 site is a key component to achieve high cellular and antiviral potency for tripeptidyl aldehyde inhibitors of M(Pro).
 A multi-pronged evaluation of aldehyde-based tripeptidyl main protease inhibitors as SARS-CoV-2 antivirals.,Ma Y, Yang KS, Geng ZZ, Alugubelli YR, Shaabani N, Vatansever EC, Ma XR, Cho CC, Khatua K, Xiao J, Blankenship LR, Yu G, Sankaran B, Li P, Allen R, Ji H, Xu S, Liu WR Eur J Med Chem. 2022 Oct 5;240:114570. doi: 10.1016/j.ejmech.2022.114570. Epub , 2022 Jun 27. PMID:35779291[1]
 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
   References ↑ Ma Y, Yang KS, Geng ZZ, Alugubelli YR, Shaabani N, Vatansever EC, Ma XR, Cho CC, Khatua K, Xiao J, Blankenship LR, Yu G, Sankaran B, Li P, Allen R, Ji H, Xu S, Liu WR. A multi-pronged evaluation of aldehyde-based tripeptidyl main protease inhibitors as SARS-CoV-2 antivirals. Eur J Med Chem. 2022 Oct 5;240:114570. PMID:35779291 doi:10.1016/j.ejmech.2022.114570
 
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