1The recent outbreak of coronavirus disease 2019 caused by SARS-CoV-2 in 2 December 2019 raised global health concerns. The viral 3-chymotrypsin-like cysteine protease 3 (3CL pro ) enzyme controls coronavirus replication and is essential for its life cycle. 3CL pro is a 4 proven drug discovery target in the case of severe acute respiratory syndrome coronavirus 5 (SARS-CoV) and middle east respiratory syndrome coronavirus (MERS-CoV). Recent studies 6 revealed that the genome sequence of SARS-CoV-2 is very similar to that of SARS-CoV. 7Therefore, herein, we analysed the 3CL pro sequence, constructed its 3D homology model, and 8 screened it against a medicinal plant library containing 32,297 potential anti-viral 9 phytochemicals/traditional Chinese medicinal compounds. Our analyses revealed that the top 10 nine hits might serve as potential anti-SARS-CoV-2 lead molecules for further optimisation and 11 drug development process to combat COVID-19. 12

The SARS-CoV-2 was confirmed to cause the global pandemic of coronavirus disease 2019 (COVID-19). The 3-chymotrypsin-like protease (3CLpro), an essential enzyme for viral replication, is a valid target to combat SARS-CoV and MERS-CoV. In this work, we present a structure-based study to identify potential covalent inhibitors containing a variety of chemical warheads. The targeted Asinex Focused Covalent (AFCL) library was screened based on different reaction types and potential covalent inhibitors were identified. In addition, we screened FDA-approved protease inhibitors to find candidates to be repurposed against SARS-CoV-2 3CLpro. A number of compounds with significant covalent docking scores were identified. These compounds were able to establish a covalent bond (C-S) with the reactive thiol group of Cys145 and to form favorable interactions with residues lining the substrate-binding site. Moreover, paritaprevir and simeprevir from FDA-approved protease inhibitors were identified as potential inhibitors of SARS-CoV-2 3CLpro. The mechanism and dynamic stability of binding between the identified compounds and SARS-CoV-2 3CLpro were characterized by molecular dynamics (MD) simulations. The identified compounds are potential inhibitors worthy of further development as COVID-19 drugs. Importantly, the identified FDA-approved anti-hepatitis-C virus (HCV) drugs paritaprevir and simeprevir could be ready for clinical trials to treat infected patients and help curb COVID-19.

The recent outbreak of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 in December 2019 raised global health concerns. The viral 3-chymotrypsin-like cysteine protease (3CLpro) enzyme, which controls coronavirus replication and is essential for its life cycle, is a proven drug discovery target in the case of severe acute respiratory syndrome coronavirus (SARS-CoV) and middle east respiratory syndrome coronavirus (MERS-CoV). Recent studies revealed that the genome sequence of SARS-CoV-2 is very similar to that of SARS-CoV. Therefore, herein, we analysed the 3CLpro sequence, constructed a 3D homology model, and screened it against a medicinal plant library containing 32,297 potential anti-viral phytochemicals/traditional Chinese medicinal compounds. Our analyses revealed that the top nine hits may serve as potential anti- SARS-CoV-2 lead molecules for further optimisation and drug development to control COVID-19.

SPAK and OSR1 are two protein kinases that have emerged as attractive targets in the discovery of novel antihypertensive agents due to their role in regulating electrolyte balance in vivo. Herein we report the identification of an allosteric pocket on the highly conserved C-terminal domains of these two kinases, which influences their activity. We also show that some known WNK signaling inhibitors bind to this allosteric site. Using in silico screening, we identified the antiparasitic agent rafoxanide as a novel allosteric inhibitor of SPAK and OSR1. Collectively, this work will facilitate the rational design of novel SPAK and OSR1 kinase inhibitors that could be useful antihypertensive agents.

The papain-like protease (PL pro ) is vital for the replication of coronaviruses (CoVs), as well as for escaping innate-immune responses of the host. Hence, it has emerged as an attractive antiviral drug-target. In this study, computational approaches were employed, mainly the structure-based virtual screening coupled with all-atom molecular dynamics (MD) simulations to computationally identify specific inhibitors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) PL pro , that can be further developed as potential pan-PL pro based broad-spectrum antiviral drugs. The sequence, structure, and functional conserveness of most deadly human CoVs PL pro were exploited, and it was revealed that functionally important catalytic triad residues are well conserved among SARS-CoV, SARS-CoV-2, and middle east respiratory syndrome coronavirus (MERS-CoV). The subsequent screening of a focused protease inhibitors database composed of ∼7000 compounds resulted in the identification of three candidate compounds, ADM_13083841, LMG_15521745, and SYN_15517940. These three compounds established conserved interactions which were further explored through MD simulations, free energy calculations, and residual energy contribution estimated by MM-PB(GB)SA method. All these compounds showed stable conformation and interacted well with the active residues of SARS-CoV-2 PL pro and showed consistent interaction profile with SARS-CoV PL pro and MERS-CoV PL pro as well. Conclusively, the reported SARS-CoV-2 PL pro specific compounds could serve as seeds for developing potent pan-PL pro based broad-spectrum antiviral drugs against deadly human coronaviruses. Moreover, the presented information related to binding site residual energy contribution could lead to further optimization of these compounds.