7smv | pdb_00007smv
Crystallization of feline coronavirus Mpro with GC376 reveals mechanism of inhibition
Structural highlights
FunctionR1AB_FIPV The replicase polyprotein of coronaviruses is a multifunctional protein: it contains the activities necessary for the transcription of negative stranded RNA, leader RNA, subgenomic mRNAs and progeny virion RNA as well as proteinases responsible for the cleavage of the polyprotein into functional products. The papain-like proteinase 1 (PLP1) and papain-like proteinase 2 (PLP2) are responsible for the cleavages located at the N-terminus of the replicase polyprotein. In addition, PLP2 possesses a deubiquitinating/deISGylating activity and processes both 'Lys-48'- and 'Lys-63'-linked polyubiquitin chains from cellular substrates. PLP2 also antagonizes innate immune induction of type I interferon by blocking the nuclear translocation of host IRF-3 (By similarity). 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. Also contains an ADP-ribose-1-phosphate (ADRP)-binding function (By similarity). The helicase which contains a zinc finger structure displays RNA and DNA duplex-unwinding activities with 5' to 3' polarity. ATPase activity is strongly stimulated by poly(U), poly(dT), poly(C), poly(dA), but not by poly(G) (By similarity). The exoribonuclease acts on both ssRNA and dsRNA in a 3' to 5' direction (By similarity). Nsp7-nsp8 hexadecamer may possibly confer processivity to the polymerase, maybe by binding to dsRNA or by producing primers utilized by the latter (By similarity). Nsp9 is a ssRNA-binding protein (By similarity). NendoU is a Mn(2+)-dependent, uridylate-specific enzyme, which leaves 2'-3'-cyclic phosphates 5' to the cleaved bond (By similarity). Publication Abstract from PubMedCoronaviruses infect a variety of hosts in the animal kingdom, and while each virus is taxonomically different, they all infect their host via the same mechanism. The coronavirus main protease (M(pro), also called 3CL(pro)), is an attractive target for drug development due to its essential role in mediating viral replication and transcription. An M(pro) inhibitor, GC376, has been shown to treat feline infectious peritonitis (FIP), a fatal infection in cats caused by internal mutations in the feline enteric coronavirus (FECV). Recently, our lab demonstrated that the feline drug, GC373, and prodrug, GC376, are potent inhibitors of SARS-CoV-2 M(pro) and solved the structures in complex with the drugs; however, no crystal structures of the FIP virus (FIPV) M(pro) with the feline drugs have been published so far. Here, we present crystal structures of FIPV M(pro)-GC373/GC376 complexes, revealing the inhibitors covalently bound to Cys144 in the active site, similar to SARS-CoV-2 M(pro). Additionally, GC376 has a higher affinity for FIPV M(pro) with lower nanomolar Ki values compared to SARS-CoV and SARS-CoV-2 M(pro). We also show that improved derivatives of GC376 have higher potency for FIPV M(pro). Since GC373 and GC376 represent strong starting points for structure-guided drug design, determining the crystal structures of FIPV M(pro) with these inhibitors are important steps in drug optimization and structure-based broad-spectrum antiviral drug discovery. Crystallization of Feline Coronavirus M(pro) With GC376 Reveals Mechanism of Inhibition.,Lu J, Chen SA, Khan MB, Brassard R, Arutyunova E, Lamer T, Vuong W, Fischer C, Young HS, Vederas JC, Lemieux MJ Front Chem. 2022 Feb 24;10:852210. doi: 10.3389/fchem.2022.852210. eCollection, 2022. PMID:35281564[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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