| Structural highlights
Function
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).[1] [2] 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.[3] 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.[4] [5] [6] [7] [8] 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.[9] [10] 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][11] 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).[12] [13] 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.[14] 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.[15] May participate in viral replication by acting as a ssRNA-binding protein.[16] 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.[17] Responsible for replication and transcription of the viral RNA genome.[18] 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.[19] [20] 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).[21] [22] [23] [24] [25] [26] 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.[27] [28]
Publication Abstract from PubMed
The main protease (M(pro), also known as 3CL protease) of SARS-CoV-2 is a high priority drug target in the development of antivirals to combat COVID-19 infections. A feline coronavirus antiviral drug, GC376, has been shown to be effective in inhibiting the SARS-CoV-2 main protease and live virus growth. As this drug moves into clinical trials, further characterization of GC376 with the main protease of coronaviruses is required to gain insight into the drug's properties, such as reversibility and broad specificity. Reversibility is an important factor for therapeutic proteolytic inhibitors to prevent toxicity due to off-target effects. Here we demonstrate that GC376 has nanomolar Ki values with the M(pro) from both SARS-CoV-2 and SARS-CoV strains. Restoring enzymatic activity after inhibition by GC376 demonstrates reversible binding with both proteases. In addition, the stability and thermodynamic parameters of both proteases were studied to shed light on physical chemical properties of these viral enzymes, revealing higher stability for SARS-CoV-2 M(pro). The comparison of a new X-ray crystal structure of M(pro) from SARS-CoV complexed with GC376 reveals similar molecular mechanism of inhibition compared to SARS-CoV-2 M(pro), and gives insight into the broad specificity properties of this drug. In both structures, we observe domain swapping of the N-termini in the dimer of the M(pro), which facilitates coordination of the drug's P1 position. These results validate that GC376 is a drug with an off-rate suitable for clinical trials.
N-Terminal Finger Stabilizes the S1 Pocket for the Reversible Feline Drug GC376 in the SARS-CoV-2 M(pro) Dimer.,Arutyunova E, Khan MB, Fischer C, Lu J, Lamer T, Vuong W, van Belkum MJ, McKay RT, Tyrrell DL, Vederas JC, Young HS, Lemieux MJ J Mol Biol. 2021 Apr 22;433(13):167003. doi: 10.1016/j.jmb.2021.167003. PMID:33895266[29]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
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- ↑ Lindner HA, Lytvyn V, Qi H, Lachance P, Ziomek E, Menard R. Selectivity in ISG15 and ubiquitin recognition by the SARS coronavirus papain-like protease. Arch Biochem Biophys. 2007 Oct 1;466(1):8-14. Epub 2007 Jul 14. PMID:17692280 doi:10.1016/j.abb.2007.07.006
- ↑ Frieman M, Ratia K, Johnston RE, Mesecar AD, Baric RS. Severe acute respiratory syndrome coronavirus papain-like protease ubiquitin-like domain and catalytic domain regulate antagonism of IRF3 and NF-kappaB signaling. J Virol. 2009 Jul;83(13):6689-705. doi: 10.1128/JVI.02220-08. Epub 2009 Apr 15. PMID:19369340 doi:10.1128/JVI.02220-08
- ↑ Chen X, Yang X, Zheng Y, Yang Y, Xing Y, Chen Z. SARS coronavirus papain-like protease inhibits the type I interferon signaling pathway through interaction with the STING-TRAF3-TBK1 complex. Protein Cell. 2014 May;5(5):369-81. doi: 10.1007/s13238-014-0026-3. Epub 2014 Mar, 14. PMID:24622840 doi:http://dx.doi.org/10.1007/s13238-014-0026-3
- ↑ Angelini MM, Neuman BW, Buchmeier MJ. Untangling membrane rearrangement in the nidovirales. DNA Cell Biol. 2014 Mar;33(3):122-7. doi: 10.1089/dna.2013.2304. Epub 2014 Jan, 10. PMID:24410069 doi:http://dx.doi.org/10.1089/dna.2013.2304
- ↑ Angelini MM, Akhlaghpour M, Neuman BW, Buchmeier MJ. Severe acute respiratory syndrome coronavirus nonstructural proteins 3, 4, and 6 induce double-membrane vesicles. mBio. 2013 Aug 13;4(4). pii: mBio.00524-13. doi: 10.1128/mBio.00524-13. PMID:23943763 doi:http://dx.doi.org/10.1128/mBio.00524-13
- ↑ Angelini MM, Neuman BW, Buchmeier MJ. Untangling membrane rearrangement in the nidovirales. DNA Cell Biol. 2014 Mar;33(3):122-7. doi: 10.1089/dna.2013.2304. Epub 2014 Jan, 10. PMID:24410069 doi:http://dx.doi.org/10.1089/dna.2013.2304
- ↑ Lin CW, Tsai FJ, Wan L, Lai CC, Lin KH, Hsieh TH, Shiu SY, Li JY. Binding interaction of SARS coronavirus 3CL(pro) protease with vacuolar-H+ ATPase G1 subunit. FEBS Lett. 2005 Nov 7;579(27):6089-94. doi: 10.1016/j.febslet.2005.09.075. Epub, 2005 Oct 6. PMID:16226257 doi:http://dx.doi.org/10.1016/j.febslet.2005.09.075
- ↑ Cottam EM, Whelband MC, Wileman T. Coronavirus NSP6 restricts autophagosome expansion. Autophagy. 2014 Aug;10(8):1426-41. doi: 10.4161/auto.29309. Epub 2014 Jun 11. PMID:24991833 doi:http://dx.doi.org/10.4161/auto.29309
- ↑ Angelini MM, Neuman BW, Buchmeier MJ. Untangling membrane rearrangement in the nidovirales. DNA Cell Biol. 2014 Mar;33(3):122-7. doi: 10.1089/dna.2013.2304. Epub 2014 Jan, 10. PMID:24410069 doi:http://dx.doi.org/10.1089/dna.2013.2304
- ↑ te Velthuis AJ, van den Worm SH, Snijder EJ. The SARS-coronavirus nsp7+nsp8 complex is a unique multimeric RNA polymerase capable of both de novo initiation and primer extension. Nucleic Acids Res. 2012 Feb;40(4):1737-47. doi: 10.1093/nar/gkr893. Epub 2011 Oct, 29. PMID:22039154 doi:http://dx.doi.org/10.1093/nar/gkr893
- ↑ te Velthuis AJ, van den Worm SH, Snijder EJ. The SARS-coronavirus nsp7+nsp8 complex is a unique multimeric RNA polymerase capable of both de novo initiation and primer extension. Nucleic Acids Res. 2012 Feb;40(4):1737-47. doi: 10.1093/nar/gkr893. Epub 2011 Oct, 29. PMID:22039154 doi:http://dx.doi.org/10.1093/nar/gkr893
- ↑ Miknis ZJ, Donaldson EF, Umland TC, Rimmer RA, Baric RS, Schultz LW. Severe acute respiratory syndrome coronavirus nsp9 dimerization is essential for efficient viral growth. J Virol. 2009 Apr;83(7):3007-18. Epub 2009 Jan 19. PMID:19153232 doi:10.1128/JVI.01505-08
- ↑ Bouvet M, Imbert I, Subissi L, Gluais L, Canard B, Decroly E. RNA 3'-end mismatch excision by the severe acute respiratory syndrome coronavirus nonstructural protein nsp10/nsp14 exoribonuclease complex. Proc Natl Acad Sci U S A. 2012 Jun 12;109(24):9372-7. doi:, 10.1073/pnas.1201130109. Epub 2012 May 25. PMID:22635272 doi:http://dx.doi.org/10.1073/pnas.1201130109
- ↑ Ahn DG, Choi JK, Taylor DR, Oh JW. Biochemical characterization of a recombinant SARS coronavirus nsp12 RNA-dependent RNA polymerase capable of copying viral RNA templates. Arch Virol. 2012 Nov;157(11):2095-104. doi: 10.1007/s00705-012-1404-x. Epub 2012 , Jul 13. PMID:22791111 doi:http://dx.doi.org/10.1007/s00705-012-1404-x
- ↑ Tanner JA, Watt RM, Chai YB, Lu LY, Lin MC, Peiris JS, Poon LL, Kung HF, Huang JD. The severe acute respiratory syndrome (SARS) coronavirus NTPase/helicase belongs to a distinct class of 5' to 3' viral helicases. J Biol Chem. 2003 Oct 10;278(41):39578-82. Epub 2003 Aug 13. PMID:12917423 doi:http://dx.doi.org/10.1074/jbc.C300328200
- ↑ Adedeji AO, Marchand B, Te Velthuis AJ, Snijder EJ, Weiss S, Eoff RL, Singh K, Sarafianos SG. Mechanism of nucleic acid unwinding by SARS-CoV helicase. PLoS One. 2012;7(5):e36521. doi: 10.1371/journal.pone.0036521. Epub 2012 May 15. PMID:22615777 doi:http://dx.doi.org/10.1371/journal.pone.0036521
- ↑ Minskaia E, Hertzig T, Gorbalenya AE, Campanacci V, Cambillau C, Canard B, Ziebuhr J. Discovery of an RNA virus 3'->5' exoribonuclease that is critically involved in coronavirus RNA synthesis. Proc Natl Acad Sci U S A. 2006 Mar 28;103(13):5108-13. Epub 2006 Mar 20. PMID:16549795 doi:http://dx.doi.org/0508200103
- ↑ Bouvet M, Debarnot C, Imbert I, Selisko B, Snijder EJ, Canard B, Decroly E. In vitro reconstitution of SARS-coronavirus mRNA cap methylation. PLoS Pathog. 2010 Apr 22;6(4):e1000863. doi: 10.1371/journal.ppat.1000863. PMID:20421945 doi:http://dx.doi.org/10.1371/journal.ppat.1000863
- ↑ Denison MR, Graham RL, Donaldson EF, Eckerle LD, Baric RS. Coronaviruses: an RNA proofreading machine regulates replication fidelity and diversity. RNA Biol. 2011 Mar-Apr;8(2):270-9. doi: 10.4161/rna.8.2.15013. Epub 2011 Mar 1. PMID:21593585 doi:http://dx.doi.org/10.4161/rna.8.2.15013
- ↑ Bouvet M, Imbert I, Subissi L, Gluais L, Canard B, Decroly E. RNA 3'-end mismatch excision by the severe acute respiratory syndrome coronavirus nonstructural protein nsp10/nsp14 exoribonuclease complex. Proc Natl Acad Sci U S A. 2012 Jun 12;109(24):9372-7. doi:, 10.1073/pnas.1201130109. Epub 2012 May 25. PMID:22635272 doi:http://dx.doi.org/10.1073/pnas.1201130109
- ↑ Smith EC, Blanc H, Surdel MC, Vignuzzi M, Denison MR. Coronaviruses lacking exoribonuclease activity are susceptible to lethal mutagenesis: evidence for proofreading and potential therapeutics. PLoS Pathog. 2013 Aug;9(8):e1003565. doi: 10.1371/journal.ppat.1003565. Epub 2013, Aug 15. PMID:23966862 doi:http://dx.doi.org/10.1371/journal.ppat.1003565
- ↑ Agostini ML, Andres EL, Sims AC, Graham RL, Sheahan TP, Lu X, Smith EC, Case JB, Feng JY, Jordan R, Ray AS, Cihlar T, Siegel D, Mackman RL, Clarke MO, Baric RS, Denison MR. Coronavirus Susceptibility to the Antiviral Remdesivir (GS-5734) Is Mediated by the Viral Polymerase and the Proofreading Exoribonuclease. mBio. 2018 Mar 6;9(2). pii: mBio.00221-18. doi: 10.1128/mBio.00221-18. PMID:29511076 doi:http://dx.doi.org/10.1128/mBio.00221-18
- ↑ Decroly E, Imbert I, Coutard B, Bouvet M, Selisko B, Alvarez K, Gorbalenya AE, Snijder EJ, Canard B. Coronavirus nonstructural protein 16 is a cap-0 binding enzyme possessing (nucleoside-2'O)-methyltransferase activity. J Virol. 2008 Aug;82(16):8071-84. doi: 10.1128/JVI.00407-08. Epub 2008 Apr 16. PMID:18417574 doi:http://dx.doi.org/10.1128/JVI.00407-08
- ↑ Bouvet M, Debarnot C, Imbert I, Selisko B, Snijder EJ, Canard B, Decroly E. In vitro reconstitution of SARS-coronavirus mRNA cap methylation. PLoS Pathog. 2010 Apr 22;6(4):e1000863. doi: 10.1371/journal.ppat.1000863. PMID:20421945 doi:http://dx.doi.org/10.1371/journal.ppat.1000863
- ↑ Arutyunova E, Khan MB, Fischer C, Lu J, Lamer T, Vuong W, van Belkum MJ, McKay RT, Tyrrell DL, Vederas JC, Young HS, Lemieux MJ. N-Terminal Finger Stabilizes the S1 Pocket for the Reversible Feline Drug GC376 in the SARS-CoV-2 M(pro) Dimer. J Mol Biol. 2021 Apr 22;433(13):167003. doi: 10.1016/j.jmb.2021.167003. PMID:33895266 doi:http://dx.doi.org/10.1016/j.jmb.2021.167003
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