5eu8
Structure of FIPV main protease in complex with dual inhibitors
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 (CoVs) can cause highly prevalent diseases in humans and animals. Feline infectious peritonitis virus (FIPV) belongs to genus alphacoronavirus, resulting in a lethal systemic granulomatous disease called FIP, which is one of the most important fatal infectious diseases of cats worldwide. No specific vaccines or drugs have been approved to treat FIP. CoV main proteases (Mpros) play a pivotal role in viral transcription and replication, making them an ideal target for drug development. Here we report the crystal structure of FIPV Mpro in complex with dual inhibitors, a zinc ion and a Michael acceptor. The complex structure elaborates a unique mechanism of two distinct inhibitors synergizing to inactivate the protease, providing structural basis to design novel antivirals and suggesting the potential to take advantage of zinc as an adjunct therapy against CoV-associated diseases. IMPORTANCE: Coronaviruses (CoVs) have the largest genome among all RNA viruses. CoV infection causes various diseases in human and animals, including severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). No approved specific drugs or vaccinations are available to treat their infections. Here we report a novel dual inhibition mechanism targeting CoV main protease (Mpro) from feline infectious peritonitis virus (FIPV), which leads to lethal systemic granulomatous disease in cats. Mpro, conserved across all CoV genomes, is essential for viral replication and transcription. We demonstrated that zinc ion and a Michael-acceptor based peptidomimetic inhibitor synergistically inactivate FIPV Mpro. We also solved the structure of FIPV Mpro complexed with two inhibitors, delineating the structural view of dual inhibition mechanism. Our study provides new insight into the pharmaceutical strategy against CoV Mpro through using zinc as an adjuvant therapy to enhance the efficacy of irreversible peptidomimetic inhibitor. The crystal structure of feline infectious peritonitis virus main protease in complex with synergetic dual inhibitors.,Wang F, Chen C, Liu X, Yang K, Xu X, Yang H J Virol. 2015 Dec 9. pii: JVI.02685-15. PMID:26656689[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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