Drug repurposing requires a limited resource, cost-effective and faster method to combat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Therefore, this in silico studies attempts to identify the drug-likeness properties of ravidasvir, an II/III phase clinical trial chronic hepatitis C drug against 3-Chymotrypsin-like protease (3CLpro) of SARS-CoV-2 to combat the ongoing coronavirus disease 2019 (COVID-19) pandemic. This protease is predominantly involved in virus replication cycle; hence it is considered as a potent drug target. The molecular docking results showed that ravidasvir was found to be potent inhibitors of 3CLpro with scoring function based binding energy is -26.7 kJ/mol. Further dynamic behaviour of apo form and complex form of ravidasvir with 3CLpro were studied using molecular dynamics (MD) simulations over 500 ns each, total 2 μs time scale. The motion of the protein was studied using principal component analysis of the MD simulation trajectories. The binding free energy calculated using MM/PBSA method from the MD simulation trajectory was -190.3 ± 70.2 kJ/mol and -106.0 ± 26.7 kJ/mol for GROMOS96 54A7 and AMBER99SB-ILDN force field, respectively. This in silico studies suggesting ravidasvir might be a potential lead molecule against SARS-CoV-2 for further optimization and drug development to combat the life-threatening COVID-19 pandemic.Communicated by Ramaswamy H. Sarma.

• MeSH
• adipáty MeSH
• benzimidazoly MeSH
• COVID-19 * farmakoterapie   MeSH
• cysteinové endopeptidasy chemie   MeSH
• inhibitory proteas chemie   MeSH
• koronavirové proteasy 3C MeSH
• lidé MeSH
• pandemie MeSH
• SARS-CoV-2 * MeSH
• simulace molekulární dynamiky MeSH
• simulace molekulového dockingu MeSH
• sukcináty MeSH
• valin analogy a deriváty   MeSH
• virové nestrukturální proteiny chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Caspase-2 is an apical protease responsible for the proteolysis of cellular substrates directly involved in mediating apoptotic signaling cascades. Caspase-2 activation is inhibited by phosphorylation followed by binding to the scaffolding protein 14-3-3, which recognizes two phosphoserines located in the linker between the caspase recruitment domain and the p19 domains of the caspase-2 zymogen. However, the structural details of this interaction and the exact role of 14-3-3 in the regulation of caspase-2 activation remain unclear. Moreover, the caspase-2 region with both 14-3-3-binding motifs also contains the nuclear localization sequence (NLS), thus suggesting that 14-3-3 binding may regulate the subcellular localization of caspase-2. Here, we report a structural analysis of the 14-3-3ζ:caspase-2 complex using a combined approach based on small angle X-ray scattering, NMR, chemical cross-linking, and fluorescence spectroscopy. The structural model proposed in this study suggests that phosphorylated caspase-2 and 14-3-3ζ form a compact and rigid complex in which the p19 and the p12 domains of caspase-2 are positioned within the central channel of the 14-3-3 dimer and stabilized through interactions with the C-terminal helices of both 14-3-3ζ protomers. In this conformation, the surface of the p12 domain, which is involved in caspase-2 activation by dimerization, is sterically occluded by the 14-3-3 dimer, thereby likely preventing caspase-2 activation. In addition, 14-3-3 protein binding to caspase-2 masks its NLS. Therefore, our results suggest that 14-3-3 protein binding to caspase-2 may play a key role in regulating caspase-2 activation. DATABASE: The atomic coordinates and structure factors have been deposited in the Protein Data Bank, www.ww pdb.org (PDB ID codes 6GKF and 6GKG).

• MeSH
• cysteinové endopeptidasy chemie   metabolismus   MeSH
• fosforylace MeSH
• jaderné lokalizační signály * MeSH
• kaspasa 2 chemie   metabolismus   MeSH
• konformace proteinů MeSH
• lidé MeSH
• maloúhlový rozptyl MeSH
• molekulární modely MeSH
• proteiny 14-3-3 chemie   metabolismus   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Ticks are ectoparasitic blood-feeders and important vectors for pathogens including arboviruses, rickettsiae, spirochetes and protozoa. As obligate blood-feeders, one possible strategy to retard disease transmission is disruption of the parasite's ability to digest host proteins. However, the constituent peptidases in the parasite gut and their potential interplay in the digestion of the blood meal are poorly understood. We have characterised a novel asparaginyl endopeptidase (legumain) from the hard tick Ixodes ricinus (termed IrAE), which we believe is the first such characterisation of a clan CD family C13 cysteine peptidase (protease) in arthropods. By RT-PCR of different tissues, IrAE mRNA was only expressed in the tick gut. Indirect immunofluorescence and EM localised IrAE in the digestive vesicles of gut cells and within the peritrophic matrix. IrAE was functionally expressed in Pichia pastoris and reacted with a specific peptidyl fluorogenic substrate, and acyloxymethyl ketone and aza-asparagine Michael acceptor inhibitors. IrAE activity was unstable at pH > or = 6.0 and was shown to have a strict specificity for asparagine at P1 using a positional scanning synthetic combinatorial library. The enzyme hydrolyzed protein substrates with a pH optimum of 4.5, consistent with the pH of gut cell digestive vesicles. Thus, IrAE cleaved the major protein of the blood meal, hemoglobin, to a predominant peptide of 4kDa. Also, IrAE trans-processed and activated the zymogen form of Schistosoma mansoni cathepsin B1 -- an enzyme contributing to hemoglobin digestion in the gut of that bloodfluke. The possible functions of IrAE in the gut digestive processes of I. ricinus are compared with those suggested for other hematophagous parasites.

• MeSH
• cysteinové endopeptidasy genetika   chemie   izolace a purifikace   MeSH
• financování organizované MeSH
• fluorescenční protilátková technika nepřímá MeSH
• fylogeneze MeSH
• hemoglobiny metabolismus   MeSH
• kathepsin B metabolismus   MeSH
• klíště enzymologie   genetika   MeSH
• klonování DNA MeSH
• messenger RNA biosyntéza   genetika   MeSH
• molekulární sekvence - údaje MeSH
• Pichia genetika   metabolismus   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• sekvenční seřazení MeSH
• transmisní elektronová mikroskopie MeSH
• trávicí systém MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH

Free propeptides are known to function as inhibitors of the parental mature cysteine cathepsins. This general rule, however, does not apply to the aminopeptidase cathepsin H. Screening of propeptide fragments for their inhibitory potency revealed no significant effect on the native mature cathepsin H. On the other hand, inhibitory interaction was established with recombinant cathepsin H that displays endopeptidase activity due to a lack of the mini-chain. This finding suggests that the propeptide-binding region is structurally rearranged during maturation processing and mini-chain formation, which impairs the effective recognition of mature cathepsin H by its own propeptide.

• MeSH
• aktivace enzymů MeSH
• cirkulární dichroismus MeSH
• cysteinové endopeptidasy chemie   metabolismus   MeSH
• financování organizované MeSH
• kathepsiny antagonisté a inhibitory   chemie   metabolismus   MeSH
• molekulární modely MeSH
• molekulární sekvence - údaje MeSH
• peptidy chemie   metabolismus   MeSH
• prekurzory enzymů chemie   metabolismus   MeSH
• sekvence aminokyselin MeSH
• terciární struktura proteinů MeSH

• MeSH
• aspartátové endopeptidasy farmakologie   chemie   MeSH
• cysteinové endopeptidasy farmakologie   chemie   MeSH
• endopeptidasy farmakologie   chemie   MeSH
• enzymy chemie   klasifikace   MeSH
• metaloendopeptidasy farmakologie   chemie   MeSH
• proteiny metabolismus   MeSH
• serinové endopeptidasy farmakologie   chemie   MeSH
• Publikační typ
• přehledy MeSH