The positive electron density in yellow and negative electron density in violet. 3.4. and molecular dynamics simulation to observe the stability and flexibility of inhibitor complexes. We have checked ADMET (absorption, distribution, metabolism, excretion and toxicity) and drug-likeness rules to scrutinize toxicity and then designed the most potent compound based on computational chemistry. Our small predicted molecule non-peptide protease inhibitors could provide a useful model in the further search for novel compounds since it has many advantages over peptidic drugs, like lower side effects, toxicity CTNND1 and less chance of drug resistance. Further, we confirmed the stability of our inhibitor-complex and conversation profile through the Molecular dynamics simulation study. Our small predicted molecule Communicated by Ramaswamy H. Sarma studies (Calligari et?al., 2020; Mary et?al., 2021). Imidazole is Dxd usually a nitrogen-containing heterocyclic ring that possesses biological and pharmaceutical importance. The imidazole derivatives possess an extensive spectrum of biological activities such as anticancer, antibacterial, antifungal and antiviral Dxd activities (Hebishy et?al., 2020; Khabnadideh et?al., 2003; Pradhan et?al., 2016; Sharma et?al., 2009). These attributes of sulfonamides and imidazole provoked us to explore the properties of these two molecules, when they and combined in a single drug-like molecule. In this present work, we have tried to observe the antiviral (anticovid19) properties of these imidazole derivatives of smx, targeting the novel viral protein Mpro. Initially, we docked the molecules against Mpro, based on the docking results, we have screened out the most potent smx derivative,4\[(E)\2\(1H\imidazol\1\yl)diazen\1\yl]\N\(5\methyl\1,2\oxazol\3\yl)benzene\1\sulfon (M10). Further, we have checked its drug-likeness and ADMET properties to achieve the most potent therapeutic. We have also performed comparative conversation profiles of M10/Mpro of four different kinds of viruses (SARS-CoV-2, SARS-CoV, Bat-CoV and MERS-CoV). We measured molecular orbital energies of M10 to assess the chemical reactivity, intermolecular interactions and kinetic stability of the compound. Finally, we have conducted MD simulation of M10-Mpro complex to observe the stability and conversation profiles of the complex. Our detailed systemic analysis portrays that our newly designed novel smx derivative has the high possibility of acting as a potent anti-COVID 19 brokers by specifically inhibiting the viral protein Mpro. 2.?Material and methods 2.1. Sequence alignment In the process of developing broad-spectrum antiviral drugs, we have searched for the common amino acid residues in the main proteases (Mpro) of SARS-CoV-2, SARS-CoV, BAT-CoV and MERS-CoV. We have done Multiple Sequence Alignment (MSA) to find homology and the evolutionary associations between four types of computer virus sequences. We have also compared with dihydropteroate synthase (DHPS) of (ADMET screening models and software approaches are often used to guideline medicinal chemistry efforts to design molecules with desired properties. ADMET has been done by evaluating water solubility, human intestinal absorption, oral bioavailability, blood-brain barrier penetration, transporter, plasma protein binding, the volume of distribution, CYP 450, toxicity, etc. by support vector machine (SVM) algorithm (Cheng et?al., 2012). 2.5. Molecular dynamics simulation All molecular dynamics (MD) simulations for the docked complex were performed using NA78 with the CHARMM36m pressure field parameter for protein and ions (Brooks et?al., 1983; Brooks & Karplus, 1989; MacKerell et?al., 1998). Swiss Param server was used to generate parameter and topology files for the docked ligands. All system was solvated in a periodic truncated water box using the TIP3P water model. Autoionize tool in VMD (Humphrey et?al., 1996) was used to neutralize the system and to maintain the salt concentration at 0.15?M by replacing water molecules with Na+ and Cl- ions. Systems were subjected to energy minimization for 5000 actions using the steepest descent method, followed by NVT and NPT equilibration for 1 and 2?ns, respectively. During the equilibration, positional restraint was applied to both protein and ligand. The heat of the system was maintained at 310?K using the damping coefficient () of 1ps?1 by Langevin dynamics. To calculate long-range electrostatic interactions in protein, Particle Mesh Ewald (PME) method was used (Darden et?al., 1993). The direct non-bonded potential cut-off was set to 12 with 2 ? pair-list distance cut-off, while the scaling factor in the range 1C4 was used during the simulation. The Langevin piston NosCHoover method was applied to maintain 1?atm constant pressure (Feller et?al., 1995; Martyna et?al., 1994). After equilibration, a 100?ns production run was performed for the system in NPT condition without any restraint with a 2 fs time step interval. RMSD of protein and ligand were calculated to check.We have also performed comparative interaction profiles of M10/Mpro of four different kinds of viruses (SARS-CoV-2, SARS-CoV, Bat-CoV and MERS-CoV). (absorption, distribution, metabolism, excretion and toxicity) and drug-likeness rules to scrutinize toxicity and then designed the most potent compound based on computational chemistry. Our small predicted molecule non-peptide protease inhibitors could provide a useful model in the further search for novel compounds since it has many advantages over peptidic drugs, like lower side effects, toxicity and less chance of drug resistance. Further, we confirmed the stability of our inhibitor-complex and interaction profile through the Molecular dynamics simulation study. Our small predicted molecule Communicated by Ramaswamy H. Sarma studies (Calligari et?al., 2020; Mary et?al., 2021). Imidazole is a nitrogen-containing heterocyclic ring that possesses biological and pharmaceutical importance. The imidazole derivatives possess an extensive spectrum of biological activities such as anticancer, antibacterial, antifungal and antiviral activities (Hebishy et?al., 2020; Khabnadideh et?al., 2003; Pradhan et?al., 2016; Sharma et?al., 2009). These attributes of sulfonamides and imidazole provoked us to explore the properties of these two molecules, when they and combined in a single drug-like molecule. In this present work, we have tried to observe the antiviral (anticovid19) properties of these imidazole derivatives of smx, targeting the novel viral protein Mpro. Initially, we docked the molecules against Mpro, based on the docking results, we have screened out the most potent smx derivative,4\[(E)\2\(1H\imidazol\1\yl)diazen\1\yl]\N\(5\methyl\1,2\oxazol\3\yl)benzene\1\sulfon (M10). Further, we have checked its drug-likeness and ADMET properties to achieve the most potent therapeutic. We have also performed comparative interaction profiles of M10/Mpro of four different kinds of viruses (SARS-CoV-2, SARS-CoV, Bat-CoV and MERS-CoV). We measured molecular orbital energies of M10 to assess the chemical reactivity, intermolecular interactions and kinetic stability of the compound. Finally, we have conducted MD simulation of M10-Mpro complex to observe the stability and interaction profiles of the complex. Our detailed systemic analysis portrays that our newly designed novel smx derivative has the high possibility of acting as a potent anti-COVID 19 agents by specifically inhibiting the viral protein Mpro. 2.?Material and methods 2.1. Sequence alignment In the process of developing broad-spectrum antiviral drugs, we have searched for the common amino acid residues in the main proteases (Mpro) of SARS-CoV-2, SARS-CoV, BAT-CoV and MERS-CoV. We have done Multiple Sequence Alignment (MSA) to find homology and the evolutionary relationships between four types of virus sequences. We have also compared with dihydropteroate synthase (DHPS) of (ADMET screening models and software approaches are often used to guide medicinal chemistry efforts to design molecules with desired properties. ADMET has been done by evaluating water solubility, human intestinal absorption, oral bioavailability, blood-brain barrier penetration, transporter, plasma protein binding, the volume of distribution, CYP 450, toxicity, etc. by support vector machine (SVM) algorithm (Cheng et?al., 2012). 2.5. Molecular dynamics simulation All molecular dynamics (MD) simulations for the docked complex were performed using NA78 with the CHARMM36m force field parameter for protein and ions (Brooks et?al., 1983; Brooks & Karplus, 1989; MacKerell et?al., 1998). Swiss Param server was used to generate parameter and topology files for the docked ligands. All system was solvated in a periodic truncated water box using the TIP3P water model. Autoionize tool in VMD (Humphrey et?al., 1996) was used to neutralize the system and to maintain the salt concentration at 0.15?M by replacing water molecules with Dxd Na+ and Cl- ions. Systems were subjected to energy minimization for 5000 steps using the steepest descent method, followed by NVT and NPT equilibration for 1 and 2?ns, respectively. During the equilibration, positional restraint was applied to both protein and ligand. The temperature of the system was maintained at 310?K using the damping coefficient () of 1ps?1 by Langevin dynamics. To calculate long-range electrostatic interactions in protein, Particle Mesh Ewald (PME) method was used (Darden et?al., 1993). The direct non-bonded potential cut-off was set to 12 with 2 ? pair-list distance cut-off, while the scaling factor in the range 1C4 was used during the simulation. The Langevin piston NosCHoover method was applied to maintain 1?atm constant pressure (Feller et?al., 1995; Martyna et?al., 1994). After equilibration, a 100?ns production run was performed for the system in NPT condition without any restraint with a 2 fs time step interval. RMSD of protein and ligand were calculated to check the equilibration of the system. RMSF of protein from M10 and smx complex were calculated to measure the residue-wise fluctuation of protein. H-bonds between protein and ligand were defined as formed when the donor-acceptor distance cut-off was less than 3.5 ? and the donor hydrogen acceptor angle Dxd was greater than 135o. 3.?Results and discussion 3.1. Sequence alignment analysis MSA results showed that there is a small similarity between (DHPS) bacteria and.