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Puromycin and the Streptomyces alboniger-derived puromycin N-acetyltransferase (PAC) enzyme form a commonly used system for selecting stably transfected cultured cells. The crystal structure of PAC has been solved using X-ray crystallography, revealing it to be a member of the GCN5-related N-acetyltransferase (GNAT) family of acetyltransferases. Based on structures in complex with acetyl-CoA or the reaction products CoA and acetylated puromycin, four classes of mutations in and around the catalytic site were designed and tested for activity. Single-residue mutations were identified that displayed a range of enzymatic activities, from complete ablation to enhanced activity relative to wild-type (WT) PAC. Cell pools of stably transfected HEK293 cells derived using two PAC mutants with attenuated activity, Y30F and A142D, were found to secrete up to three-fold higher levels of a soluble, recombinant target protein than corresponding pools derived with the WT enzyme. A third mutant, Y171F, appeared to stabilise the intracellular turnover of PAC, resulting in an apparent loss of selection stringency. Our results indicate that the structure-guided manipulation of PAC function can be utilised to enhance selection stringency for the derivation of mammalian cell lines secreting elevated levels of recombinant proteins.

Background: Human cardiac biopsies are widely used in clinical and fundamental research to decipher molecular events that characterize cardiac physiological and pathophysiological states. One of the main approaches relies on the analysis of semi-quantitative immunoblots that reveals alterations in protein expression levels occurring in diseased hearts. To maintain semiquantitative results, expression level of target proteins (TP) must be standardized. The expression of housekeeping proteins (HKP) is commonly used to this purpose. Methods and Results: We evaluated the stability of HKP expression (actin, b-tubulin, GAPDH, vinculin and calsequestrin [CSQ]) and total protein staining (TPS) within control (coefficient of variation) and comparatively with ischemic human heart biopsies (P value). All HKP exhibited a high level of intragroup (i.e., actin, b-tubulin and GAPDH) and/or intergroup variability (i.e., GAPDH, vinculin and CSQ). Among all, we found TPS to exhibit the highest degree of stability within and between groups, which makes of this reference the best to study protein expression level in human biopsies from ischemic hearts and age-matched controls. In addition, we illustrated that using an inappropriate reference protein marker misleads interpretation on SERCA2 and cMyBPC expression level after myocardial infarction. Conclusions: These emphasize the need to standardize the level of protein expression with TPS in comparative immunoblot studies on human samples from control and diseased hearts.

Chemical modification of proteins is enormously useful for characterizing protein function in complex biological systems and for drug development. Selective labeling of native or endogenous proteins is challenging owing to the existence of distinct functional groups in proteins and in living systems. Chemistry for rapid and selective labeling of proteins remains in high demand. Here we have developed novel affinity labeling probes using benzotriazole (BTA) chemistry. We showed that affinity-based BTA probes selectively and covalently label a lysine residue in the vicinity of the ligand binding site of a target protein with a reaction half-time of 28-42 s. The reaction rate constant is comparable to the fastest biorthogonal chemistry. This approach was used to selectively label different cytosolic and membrane proteins in vitro and in live cells. BTA chemistry could be widely useful for labeling of native/endogenous proteins, target identification and development of covalent inhibitors.

BACKGROUND: Downstream processing of soluble recombinant proteins from Escherichia coli is complicated by the need to access the intracellular product by cell disruption and to separate the target protein from impurities, particularly host cell protein, DNA, endotoxins and lipids. We previously demonstrated the ability of the E. coli X‐press strain to leak high amounts of product to the culture medium without sacrificing viability. In this case study, we assessed the economic and ecological benefit of this strain for downstream processing in direct comparison to the industrial standard E. coli BL21(DE3). Staphylococcal Protein A was used as a model protein. We performed recombinant protein production, primary recovery and capture by anion exchange chromatography at laboratory scale, and used the data obtained for estimating costs and resource consumption by economic modeling. RESULTS: After primary recovery, the X‐press process resulted in a 1.5‐fold higher product purity, a 150‐fold lower DNA, 3.5‐fold lower endotoxin and 3.4‐fold lower lipid load compared to BL21(DE3). Consequently, anion exchanger binding capacity was increased 2.7‐fold and purity and concentration of the eluate also was increased. Extracellular protein production with X‐press resulted in a 25% reduction of costs and a 36% reduction of both water usage and water‐related CO₂ emissions compared to intracellular production with BL21(DE3). CONCLUSIONS: This case study performed with stapyhlococcal Protein A demonstrated the potential of E. coli X‐press to reduce costs for downstream processing and improve the environmental footprint by simplified primary recovery, lower impurity load and consequently higher chromatographic efficiency. © 2021 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Rhodococcus bacteria are a promising platform for biodegradation, biocatalysis, and biosynthesis, but the use of rhodococci is hampered by the insufficient number of both platform strains for expression and promoters that are functional and thoroughly studied in these strains. To expand the list of such strains and promoters, we studied the expression capability of the Rhodococcus rhodochrous M33 strain, and the functioning of a set of recombinant promoters in it. We showed that the strain supports superexpression of the target enzyme (nitrile hydratase) using alternative inexpensive feedings-acetate and urea-without growth factor supplementation, thus being a suitable expression platform. The promoter set included Ptuf (elongation factor Tu) and Psod (superoxide dismutase) from Corynebacterium glutamicum ATCC13032, Pcpi (isocitrate lyase) from Rhodococcus erythropolis PR4, and Pnh (nitrile hydratase) from R. rhodochrous M8. Activity levels, regulation possibilities, and growth-phase-dependent activity profiles of these promoters were studied in derivatives of the M33 strain. The activities of the promoters were significantly different (Pcpi < Psod ≪ Ptuf < Pnh), covering 103-fold range, and the most active Pnh and Ptuf produced up to a 30-50% portion of target protein in soluble intracellular proteins. On the basis of the mRNA quantification and amount of target protein, the production level of Pnh was positioned close to the theoretical upper limit of expression in a bacterial cell. A selection method for the laboratory evolution of such active promoters directly in Rhodococcus was also proposed. Concerning regulation, Ptuf could not be regulated (2-fold change), while others were tunable (6-fold for Psod, 79-fold for Pnh, and 44-fold for Pcpi). The promoters possessed four different activity profiles, including three with peak of activity at different growth phases and one with constant activity throughout the growth phases. Ptuf and Pcpi did not change their activity profile under different growth conditions, whereas the Psod and Pnh profiles changed depending on the growth media. The results allow flexible construction of Rhodococcus strains using the studied promoters, and demonstrate a valuable approach for complex characterization of promoters intended for biotechnological strain construction.

The disruption of the sumoylation pathway affects processes controlled by the two phototropins (phots) of Arabidopsis thaliana, phot1 and phot2. Phots, plant UVA/blue light photoreceptors, regulate growth responses and fast movements aimed at optimizing photosynthesis, such as phototropism, chloroplast relocations and stomatal opening. Sumoylation is a posttranslational modification, consisting of the addition of a SUMO (SMALL UBIQUITIN-RELATED MODIFIER) protein to a lysine residue in the target protein. In addition to affecting the stability of proteins, it regulates their activity, interactions and subcellular localization. We examined physiological responses controlled by phots, phototropism and chloroplast movements, in sumoylation pathway mutants. Chloroplast accumulation in response to both continuous and pulse light was enhanced in the E3 ligase siz1 mutant, in a manner dependent on phot2. A significant decrease in phot2 protein abundance was observed in this mutant after blue light treatment both in seedlings and mature leaves. Using plant transient expression and yeast two-hybrid assays, we found that phots interacted with SUMO proteins mainly through their N-terminal parts, which contain the photosensory LOV domains. The covalent modification in phots by SUMO was verified using an Arabidopsis sumoylation system reconstituted in bacteria followed by the mass spectrometry analysis. Lys 297 was identified as the main target of SUMO3 in the phot2 molecule. Finally, sumoylation of phot2 was detected in Arabidopsis mature leaves upon light or heat stress treatment.

Drug target discovery is the basis of drug screening. It elucidates the cause of disease and the mechanism of drug action, which is the essential of drug innovation. Target discovery performed in biological systems is complicated as proteins are in low abundance and endogenous compounds may interfere with drug binding. Therefore, methods to track drug-target interactions in biological matrices are urgently required. In this work, a Fe3O4 nanoparticle-based approach was developed for drug-target screening in biofluids. A known ligand-protein complex was selected as a principle-to-proof example to validate the feasibility. After incubation in cell lysates, ligand-modified Fe3O4 nanoparticles bound to the target protein and formed complexes that were separated from the lysates by a magnet for further analysis. The large surface-to-volume ratio of the nanoparticles provides more active sites for the modification of chemical drugs. It enhances the opportunity for ligand-protein interactions, which is beneficial for capturing target proteins, especially for those with low abundance. Additionally, a one-step magnetic separation simplifies the pre-processing of ligand-protein complexes, so it effectively reduces the endogenous interference. Therefore, the present nanoparticle-based approach has the potential to be used for drug target screening in biological systems., Graphical abstract Image 1, Highlights • Fe3O4 NPs were made hydrophilic to adequately disperse in the cell lysate and fully contact with target proteins. • The magnetic property of the NPs allowed one-step isolation while maintaining ligand-protein non-covalent bindings. • It enabled the capture of low abundant targets in biological matrices while eliminated the endogenous interference.

A new series of fused tricyclic coumarin derivatives were designed, synthesized by a simple and convenient method, starting from 4-hydroxycoumarin and virtually screened by molecular docking on the target protein 3FRZ (PDB ID: 3FRZ), a HCV RNA-dependent RNA polymerase, for potency against hepatitis C virus (HCV). Efficient binding to the target protein was found for most of the synthesized compounds.

Sobhi M Gomha,1,2 Hyam A Abdelhady,2 Doaa ZH Hassain,2 Aboubakr H Abdelmonsef,3 Mohamed El-Naggar,4 Mahmoud M Elaasser,5 Huda K Mahmoud2 1Chemistry Department, Faculty of Science, Islamic University in Almadinah Almonawara, Almadinah Almonawara, 42351, Saudi Arabia; 2Chemistry Department, Faculty of Science, University of Cairo, Giza, Egypt; 3Chemistry Department, Faculty of Science, South Valley University, Qena, 83523, Egypt; 4Chemistry Department, Faculty of Sciences, University of Sharjah, Sharjah, 27272, United Arab Emirates; 5The Regional Center for Mycology and Biotechnology, Al-Azhar University, Cairo, 11371, EgyptCorrespondence: Sobhi M Gomha Email s.m.gomha@gmail.comAboubakr H Abdelmonsef Email aboubakr.ahmed@sci.svu.edu.egIntroduction: Hybrid drug design has developed as a prime method for the development of novel anticancer therapies that can theoretically solve much of the pharmacokinetic disadvantages of traditional anticancer drugs. Thus a number of studies have indicated that thiazole-thiophene hybrids and their bis derivatives have important anticancer activity. Mammalian Rab7b protein is a member of the Rab GTPase protein family that controls the trafficking from endosomes to the TGN. Alteration in the Rab7b expression is implicated in differentiation of malignant cells, causing cancer.Methods: 1-(4-Methyl-2-(2-(1-(thiophen-2-yl) ethylidene) hydrazinyl) thiazol-5-yl) ethanone was used as building block for synthesis of novel series of 5-(1-(2-(thiazol-2-yl) hydrazono) ethyl) thiazole derivatives. The bioactivities of the synthesized compounds were evaluated with respect to their antitumor activities against MCF-7 tumor cells using MTT assay. Computer-aided docking protocol was performed to study the possible molecular interactions between the newly synthetic thiazole compounds and the active binding site of the target protein Rab7b. Moreover, the in silico prediction of adsorption, distribution, metabolism, excretion (ADME) and toxicity (T) properties of synthesized compounds were carried out using admetSAR tool.Results: The results obtained showed that derivatives 9 and 11b have promising activity (IC50 = 14.6 ± 0.8 and 28.3 ± 1.5 μM, respectively) compared to Cisplatin (IC50 = 13.6 ± 0.9 μM). The molecular docking analysis reveals that the synthesized compounds are predicted to be fit into the binding site of the target Rab7b. In summary, the synthetic thiazole compounds 1– 17 could be used as potent inhibitors as anticancer drugs.Conclusion: Promising anticancer activity of compounds 9 and 11 compared with cisplatin reference drug suggests that these ligands may contribute as lead compounds in search of new anticancer agents to combat chemo-resistance.Keywords: thiazoles, hydrazones, hydrazonoyl halides, docking, Rab7b, MCF-7

Background Moringa oleifera is a common vegetable in many countries since ancient times, possesses numerous phenolic compounds having a wide array of biological activities. It possesses anticancer activity that can be used to develop new drugs for treatment of various types of cancers. The current study was conducted to evaluate the composition of phenolic compounds and in vitro and in silico anticancer activities of M. oleifera leaves extracts. The leaves of M. oleifera were subjected to extraction for solvent fraction using n-hexane, chloroform, ethyl acetate, butanol, and aqueous solvents. The solvent fractions were tested for anticancer activity in vitro against Hela cancer cell line and screened for phenolic compounds through reversed-phase high-performance liquid chromatography. The molecular docking approach was employed to check binding conformations of phytochemicals against the target protein. Result The result revealed that all the solvent fractions possess in vitro anticancer activity against Hela cancer cell line. The n-hexane fraction showed a 50% reduction in Hela cancer cell viability at 416 μg mL−1 as compared to control. The extracts of solvent-fraction contained 10 phenolic compounds viz. quercetin, gallic acid, sinapic acid, vanillic acid, 4-hydroxy-3-methoxy benzoic acid, p-coumaric acid, m-coumaric acid, 4-hydroxy-3-methoxy cinnamic acid, caffeic acid, and syringic acid. Molecular docking studies revealed that the ligands bind within the active site of target protein have good binding energy values. Conclusion This study shows that M. oleifera leaves may have the potential to inhibit cancer cell growth and improving human health in addition to food ingredient innovations. Based on in vitro and in silico results, the phytochemicals from M. oleifera leaves can be used as leading drugs to treat cancer. Graphical abstract

Since December 2019, a pneumonia caused by a novel coronavirus (SARS-CoV-2) emerged in China and has rapidly spread around the world. The virus has caused a global outbreak of viral pneumonia, which has been known as coronavirus disease (COVID-19). This study aims to examine known direct acting antivirals (DAA) against SARS-CoV-2 papin like protease. A number of known antiviral drugs were tested as potential SARS-CoV-2 virus inhibitors using the molecular docking analysis to examine the free natural affinity of the binding ligand to catalytic residues and substrate binding pockets without forcing the docking of ligand to active site. SARS-CoV-2 papin like protease solved structure (PDB ID: 6W9C) is targeted by direct acting antiviral drugs. The geometry of all inhibitors was optimized using Avogadro software. Molecular Docking was performed using AutoDock Vina software. Protein-Ligand Interaction Profiler (PLIP) web server was used to analyze the interactions formed between drugs and SARS-CoV-2 PLpro. Mycophenolic acid and 4′-Tosyl Mycophenolic Acid-d3 was tested against SARS-CoV-2 papin like protease mutant C111S (PDB ID: 6WRH). Mycophenolic acid showed mild efficacy against the mutant strain. The molecular docking analysis results indicated that Mycophenolic acid and 4′-Tosyl Mycophenolic Acid-d3 has good binding affinities to the protein drug target (-5.72 Kcal/mol and -5.72 Kcal/mol) and showed the highest probabilities to bind to catalytic residues of target protein (30% and 50%) respectively, suggesting their potential use for COVID-19 treatment. Molecular dynamic simulation was used to confirm the stability of the complexes formed.

It is of interest to document the moelcular docking analysis of SARS-CoV-2 linked RNA dependent RNA polymerase (RdRp) with compounds from Plectranthus amboinicus. Hence, we report the binding features of rutin, Luteolin, Salvianolic acid A, Rosmarinic acid and p-Coumaric acid with the target protein SARS-CoV-2 linked RNA dependent RNA polymerase (RdRp) for further consideration.

A novel coordination polymer based on Co(II) was synthesized by reacting Co(NO3)2·6H2O with H2DCTP in the existence of a second nitrogen-donor L ligand through a mixed-ligand approach. Its chemical formula is [Co2(OH)(L)(DCTP)1.5]n (1, H2DCTP = 2,5-dichloroterephthalic acid and L = 1,3-bis[5,6-methylbenzimidazol-1-yl]propane). Biological experiments were conducted for the evaluation of the compound’s protective effect on brain injury after subarachnoid hemorrhage. Neuron-specific enolase and adrenomedullin contents were determined. Furthermore, the expression levels of tumor necrosis factor receptor-associated factor 6 in the brain tissue were measured by Western blot after treatment with the compound. Molecular docking study indicated that the carboxyl groups on the p-dichlorobenzene were the main active groups that reacted with the target protein, whereas nitrogenous groups were the supportive groups for the entire metal complex.

Background: Coagulation factor XIIIa(FXIIIa) plays a critical role in the final stage of blood coagulation. It is extremely important in wound healing, tissue repairing and promoting cell adhesion. The deficiency of the coagulation factor can cause hemorrhage and slow wound healing. Objective: In this study, recombinant pPICZαC-FXIIIa was expressed in Pichia pastoris, purified as well as its biological activity was determined. Methods: The FXIIIa fragment obtained from the human placenta was inserted into pPICZαC to obtain pPICZαC-FXIIIa, which was transformed into X33 after linearization, and FXIIIa inserted into Pichia pastoris X33 was screened for methanol induction. The expressed product was identified by western blotting, then the supernatant was purified by affinity chromatography, and the purified product was determined by plasma coagulation experiment. Results: Polymerase Chain Reaction(PCR) showed that the FXIIIa fragment of 2250 bp was inserted successfully into pPICZαC. The expression and purification products of the same molecular weight as target protein(about 83 kDa) were obtained, which solidified significantly when reacted with plasma. Conclusion: The expression and purification products were successful, with sufficient biological activity, which can be used as a candidate FXIIIa hemostatic agent in genetic engineering.

In the world plagued by the emergence of new diseases, it is essential that we accelerate the drug design process to develop new therapeutics against them. In recent years, deep learning-based methods have shown some success in ligand-based drug design. Yet, these methods face the problem of data scarcity while designing drugs against a novel target. In this work, the potential of deep learning and molecular modeling approaches was leveraged to develop a drug design pipeline, which can be useful for cases where there is limited or no availability of target-specific ligand datasets. Inhibitors of the homologues of the target protein were screened at the active site of the target protein to create an initial target-specific dataset. Transfer learning was used to learn the features of the target-specific dataset. A deep predictive model was utilized to predict the docking scores of newly designed molecules. Both these models were combined using reinforcement learning to design new chemical entities with an optimized docking score. The pipeline was validated by designing inhibitors against the human JAK2 protein, where none of the existing JAK2 inhibitors were used for training. The ability of the method to reproduce existing molecules from the validation dataset and design molecules with better binding energy demonstrates the potential of the proposed approach.

Using polymerase chain reaction (PCR)-mediated recombination, single ribonucleic acid (RNA) chains containing bifunctional RNA sequences involving substrate binding and phosphorescent signaling were prepared. For substrate binding and phosphorescent labeling, thrombin- or lysozyme-binding and ruthenium complex-binding RNA aptamer sequences were used. It was demonstrated that the structural properties of the conjugated RNAs showed similar characteristics to the original aptamers using circular dichroism (CD) spectrometry. Furthermore, electrophoretic mobility shift assays of the proteins and phosphorescence measurements of the ruthenium complexes suggested that the binding abilities of the conjugated RNAs maintained the original aptamer functions. Finally, it was established that the conjugated RNA sequences were suitable as phosphorescent RNA probes for protein cognates. Therefore, this “one stroke drawing” strategy is proposed as a promising biological method for the generation of phosphorescent RNA probes that do not culminate in a loss of function of the original aptamers. Using polymerase chain reaction (PCR)-mediated recombination, we prepared single ribonucleic acid (RNA) chains containing bifunctional RNA sequences involving substrate binding and phosphorescent signaling. The prepared RNAs largely maintained the functionalities of the original aptamers even after bifunctionalization. We demonstrated that the bifunctionalized RNAs can be used as phosphorescent detection probes for the target protein. Therefore, we suggested that the PCR-mediated “one stroke drawing” is a promising strategy for the preparation of RNA detection probes.

Dehydroalanine (Dha) residues are attractive noncanonical amino acids that occur naturally in ribosomally synthesised and post‐translationally modified peptides (RiPPs). Dha residues are attractive targets for selective late‐stage modification of these complex biomolecules. In this work, we show the selective photocatalytic modification of dehydroalanine residues in the antimicrobial peptide nisin and in the proteins small ubiquitin‐like modifier (SUMO) and superfolder green fluorescent protein (sfGFP). For this purpose, a new water‐soluble iridium(III) photoredox catalyst was used. The design and synthesis of this new photocatalyst, [Ir(dF(CF3)ppy)2(dNMe3bpy)]Cl3, is presented. In contrast to commonly used iridium photocatalysts, this complex is highly water soluble and allows peptides and proteins to be modified in water and aqueous solvents under physiologically relevant conditions, with short reaction times and with low reagent and catalyst loadings. This work suggests that photoredox catalysis using this newly designed catalyst is a promising strategy to modify dehydroalanine‐containing natural products and thus could have great potential for novel bioconjugation strategies., Bio‐orthogonal modification of dehydroalanine residues in peptides and proteins is achieved by photoredox catalysis with a newly designed water‐soluble IrIII complex in aqueous media and a variety of zinc benzylsulfinates as reagents.

Short synthetic peptide molecules which bind to a specific target protein with a high affinity to exert its function are known as peptide aptamers. The high specificity of aptamers with small-molecule targets (metal ions, dyes and theophylline; ATP) is within 1 pM and 1 μM range, whereas with the proteins (thrombin, CD4 and antibodies) it is in the nanomolar range (which is equivalent to monoclonal antibodies). The recently identified coronavirus (SARS-CoV-2) genome encodes for various proteins, such as envelope, membrane, nucleocapsid, and spike protein. Among these, the protein necessary for the virus to enter inside the host cell is spike protein. The work focuses on designing peptide aptamer targeting the spike receptor-binding domain of SARS-CoV-2. The peptide aptamer has been designed by using bacterial Thioredoxin A as the scaffold protein and an 18-residue-long peptide. The tertiary structure of the peptide aptamer is modeled and docked to spike receptor-binding domain of SARS CoV2. Molecular dynamic simulation has been done to check the stability of the aptamer and receptor-binding domain complex. It was observed that the aptamer binds to spike receptor-binding domain of SARS-CoV-2 in a similar pattern as that of ACE2. The aptamer–receptor-binding domain complex was found to be stable in a 100 ns molecular dynamic simulation. The aptamer is also predicted to be non-antigenic, non-allergenic, non-hemolytic, non-inflammatory, water-soluble with high affinity toward ACE2 than serum albumin. Thus, peptide aptamer can be a novel approach for the therapeutic treatment for SARS-CoV-2. Graphical abstract

Background Growth factors (GFs) are signaling proteins that affect cellular processes such as growth, proliferation, and differentiation. GFs are used as cosmeceuticals, exerting anti-wrinkle, anti-aging, and whitening effects, and also as pharmaceuticals to treat wounds, growth failure, and oral mucositis. However, in mammalian and bacterial cells, low productivity and expression in inclusion bodies, respectively, of GFs does not satisfy the consumer demand. Here, we aimed to develop a bacterial expression system that produces high yields of soluble GFs that can be purified in their native forms. Results We present Fh8, an 8-kDa peptide from Fasciola hepatica with an N-terminal hexa-histidine (6HFh8), as a fusion partner for enhanced human GF production in recombinant Escherichia coli. The fusion partner harboring a tobacco etch virus (TEV) protease cleavage site was fused to the N-terminus of 10 human GFs: acidic and basic fibroblast growth factors (aFGF and bFGF, respectively), epidermal growth factor (EGF), human growth hormone (hGH), insulin-like growth factor 1 (IGF-1), vascular endothelial growth factor 165 (VEGF165), keratinocyte growth factor 1 (KGF-1), placental growth factor (PGF), stem cell factor (SCF), and tissue inhibitor of metalloproteinase 1 (TIMP-1). The fusion proteins were expressed in E. coli under the control of T7 promoter at three temperatures (25 °C, 30 °C, and 37 °C). All individual fusion proteins, except for SCF and TIMP-1, were successfully overexpressed in cytoplasmic soluble form at more than one temperature. Further, the original aFGF, IGF-1, EGF, and VEGF165 proteins were cleaved from the fusion partner by TEV protease. Five-liter fed-batch fermentation approaches for the 6HFh8-aFGF (lacking disulfide bonds) and 6HFh8-VEGF165 (a cysteine-rich protein) were devised to obtain the target protein at concentrations of 9.7 g/l and 3.4 g/l, respectively. The two GFs were successfully highly purified (> 99% purity). Furthermore, they exerted similar cell proliferative effects as those of their commercial equivalents. Conclusions We demonstrated that 6HFh8-GF fusion proteins could be overexpressed on a g/l scale in the cytoplasm of E. coli, with the GFs subsequently highly purified and maintaining their biological activity. Hence, the small protein 6HFh8 can be used for efficient mass-production of various GFs.

Graphical abstract, The new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes pathological pulmonary symptoms. Most efforts to develop vaccines and drugs against this virus target the spike glycoprotein, particularly its S1 subunit, which is recognised by angiotensin-converting enzyme 2. Here we use the in-house developed tool CaverDock to perform virtual screening against spike glycoprotein using a cryogenic electron microscopy structure (PDB-ID: 6VXX) and the representative structures of five most populated clusters from a previously published molecular dynamics simulation. The dataset of ligands was obtained from the ZINC database and consists of drugs approved for clinical use worldwide. Trajectories for the passage of individual drugs through the tunnel of the spike glycoprotein homotrimer, their binding energies within the tunnel, and the duration of their contacts with the trimer’s three subunits were computed for the full dataset. Multivariate statistical methods were then used to establish structure-activity relationships and select top candidate for movement inhibition. This new protocol for the rapid screening of globally approved drugs (4359 ligands) in a multi-state protein structure (6 states) showed high robustness in the rate of finished calculations. The protocol is universal and can be applied to any target protein with an experimental tertiary structure containing protein tunnels or channels. The protocol will be implemented in the next version of CaverWeb (https://loschmidt.chemi.muni.cz/caverweb/) to make it accessible to the wider scientific community.

The current work represents the design and synthetic approaches of a new set of compounds 6–10 bearing the 1,4-dimethyl-2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonamide scaffold. The biological evaluation revealed that most of the new compounds were promising selective dipeptidyl peptidase-IV (DPP-4) inhibitors and in vivo hypoglycemic agents utilizing linagliptin as a standard drug. The acute toxicity examination confirmed the safety profile of all compounds. Molecular docking studies related the significant DPP-4 suppression activity of compounds 9a, 10a, 10f, 10g to their nice fitting in the active pocket of DPP-4. In addition, the molecular dynamic study exhibited the stability of both 10a and 10g within the active site of DPP-4. The QSAR study showed that the difference between the predicted activities is very close to the experimental suppression effect. Moreover, both compounds 10a and 10g obeyed Lipinski's rule, indicating their efficient oral bioavailability. Compound 10a was radiolabeled, forming the 131I-SQ compound 10a to study the pharmacokinetic profile of this set of compounds. The biodistribution pattern hit the target protein since the tracer accumulated mainly in the visceral organs where DPP-4 is secreted in a high-level, thus with consequent stimulation of insulin secretion, leading to the target hypoglycemic effect.

Targeted protein degradation has emerged as a new paradigm to manipulate cellular proteostasis. Proteolysis-targeting chimeras (PROTACs) are bifunctional small molecules that recruit an E3 ligase to a target protein of interest, promoting its ubiquitination and subsequent degradation. Here, we report the development of antibody-based PROTACs (AbTACs), fully recombinant bispecific antibodies that recruit membrane-bound E3 ligases for the degradation of cell-surface proteins. We show that an AbTAC can induce the lysosomal degradation of programmed death-ligand 1 by recruitment of the membrane-bound E3 ligase RNF43. AbTACs represent a new archetype within the PROTAC field to target cell-surface proteins with fully recombinant biological molecules.

PD/BD/105753/2014 PTDC/BII-BIO/28878/2017 UIDB/04378/ 2020 POCI-01-0145-FEDER-007728 After more than one hundred and thirty thousand protein structures determined by X-ray crystallography, the challenge of protein crystallization for 3D structure determination remains. In the quest for additives for efficient protein crystallization, inorganic materials emerge as an alternative. Magnetic particles (MPs) are versatile inorganic materials, easy to use, modify and manipulate in a wide range of biological assays. The potential of using functionalised MPs as crystallization chaperones for protein crystallization was shown in this work. MPs with distinct coatings were rationally designed to promote protein crystallization by affinity-triggered heterogeneous nucleation. Hen egg white lysozyme (HEWL) and trypsin, were crystallized in the presence of MPs either bare or coated with a polysaccharide (chitin) or a protein (casein), respectively. The addition of MPs was characterized in terms of bound protein to the MPs, crystal morphology, time-lapse of crystal emergence, crystallization yield fold change and crystal diffraction quality for structure determination. The MPs additives have shown to bind to the respective target protein, and to promote nucleation and crystal growth without compromising crystal morphology. On the other hand, MPs addition led to faster detectable crystal emergence and up to 13 times higher crystallization yield, addressing some the challenges in protein crystallization, the main bottleneck of macromolecular crystallography. Structure determination of the protein crystallized in the presence of MPs revealed that the structural characteristics of the protein remained unchanged, as shown by the superposition with PDB annotated proteins. Moreover, and unlike most reported cases, it was possible to exclude the inhibitor benzamidine during trypsin crystallisation, which is a remarkable result opening new prospects in enzyme engineering and drug design. Our results show that MPs coated with affinity ligands to target proteins can be used as controlled and tailor-made crystallization inducers. authorsversion published

Background: Stenotrophomonas maltophilia is a multi-drug resistant, gram-negative bacterium that causes opportunistic infections and is associated with high morbidity and mortality in severely immunocompromised individuals. Aim: The study aimed to find out the drug target and a novel inhibitor for Stenotrophomonas maltophilia. Objectives: The current study focused on identifying specific drug targets by subtractive genomes analysis to determine the novel inhibitor for the specified target protein by virtual screening, molecular docking, and molecular simulation approach. Materials and Methods: In this study, we performed a subtractive genomics approach to identify the novel drug target for S.maltophilia. After obtaining the specific target, the next step was to identify inhibitors that include calculating 2D similarity search, molecular docking, and molecular simulation for drug development for S.maltophilia. Results: With an efficient subtractive genomic approach, five unique targets as the impressive therapeutics founded out of 4386 protein genes. In which UDP-D-acetylmuramic (murF) was the most remarkable target. Further virtual screening, docking, and dynamics resulted in the identification of seven novel inhibitors. Conclusion: Further, in vitro and in vivo bioassay of the identified novel inhibitors could facilitate effective drug use against S.maltophilia.

This study aims to investigate the general social perspective related to black tea (Camellia sinensis) as a traditional treatment in Indonesia, the potency of bioactive compounds in black tea as a dual inhibitor of the replication of HIV-1 as it inhibits the chemical interactions between ligands and target protein domain. The samples is prepared from specific databases that is about HIV-1 target protein, black tea chemical compounds, and HIV-1 drug compounds as positive control. After that the virtual screening, protein-ligand interaction, and molecular visualization tests were performed. Thirteen black tea compounds obtained from the database and 2 control compounds consisting of neverapine and darunavir. In addition, the 3D structure of the target protein from HIV-1 consisting of reverse transcriptase (RT) (ID 3LP1) and protease (PR) (ID 4HLA) was obtained from a protein database. Interestingly, the social perspective regarding HIV-1 treatment is predicted to be more likely to choose traditional medicine compared to the use of antiretroviral (ARV) drugs. Traditional medicine with black tea may be very popular among many people. In conclusion, almost all chemical compounds contained in black tea can inhibit the HIV-1 replication. Furthermore, there are two compounds that play an important role in the process because it is predicted to inhibit the biological activity of PR and RT in HIV-1, (−)-epicatechin-gallate and epigallocatechin-gallate called dual inhibitors.

We review recent advances of Ubiquitin-Proteasome System (UPS)-based research and development with increased focus as drug discovery approaches and introduce applications of chimera-type small molecule compounds (SNIPER/PROTAC) that selectively promote degradation of a drug target protein. UPS makes the point (polyubiquitin chain) of targeting protein as a substrate and has a property that degrade the target protein with proteasome. Protein knockout technologies degrade the drug target protein by apply this protein degrading system. In current technologies, polyubiquitin chains are artificially added to the drug target proteins through small molecules and introduce degradation of the target proteins. The approaches are divided into 2 types, one of which is E3 modulator-based technology represented by thalidomide, the other one is chimera compound-based technology represented by SNIPER/PROTAC. Furthermore, novel technologies are practically used to identify small molecule E3 binders as well as E3-targeting protein binders. These new approaches are expected to contribute to the efficient UPS-based drug discovery.

Herein, we describe an isothermal proximity CRISPR Cas12a assay that harnesses the target-induced indiscrimitive single-stranded DNase activity of Cas12a for the quantitative profiling of gene expression at the mRNA level and detection of proteins with high sensitivity and specificity. The target recognition is achieved through proximity binding rather than recognition by CRISPR RNA (crRNA), which allows for flexible assay design. A binding-induced primer extension reaction is used to generate a predesigned CRISPR-targetable sequence as a barcode for further signal amplification. Through this dual amplification protocol, we were able to detect as low as 1 fM target nucleic acid and 100 fM target protein isothermally. The practical applicability of this assay was successfully demonstrated for the temporal profiling of interleukin-6 gene expression during allergen-mediated mast cell activation., Herein, we develop an isothermal proximity CRISPR Cas12a assay that harnesses the target-induced collateral cleavage activity of Cas12a for the quantitative profiling of gene expression and detection of proteins with high sensitivity and specificity.

An ecdysone receptor (EcR) is a nuclear receptor protein, a prime target for pesticide development processes due to its involvement in the growth and development of insects. The activation of EcRs leads to hasty and premature development of insects, thereby preventing them from destroying the crops. The high cost, environmental toxicity, and resistance towards the currently available insecticides have resulted in a growing demand for the development of economical and environment-friendly pesticides with unique insecticidal activity. Several reports on resistance towards conventional pesticides like ponasterone A and RH-5849 were reported in recent years. In this study, the plant derived (C. deodara), in-house synthesized molecules with benzosuberene scaffolds were screened for their ability to interact with the EcRs of both Hemiptera and Coleoptera. The preliminary analysis by molecular docking showed that some of our molecules exhibited excellent binding with the target protein. Moreover, molecular dynamics simulations, binding free energy estimations, and umbrella sampling simulations were conducted to validate the docking results. Our analysis revealed Com-7 and Com-3 as potential EcR agonists to target Hemiptera and Coleoptera, respectively. Also, Com-8 and Com-12 could be used as lead compounds against the EcR of Coleoptera.

The aim of the present study was to investigate the pharmacological mechanism of matrine in treatment of COVID-19 combined with liver injury. Potential targets related to matrine, COVID-19 and liver injury were identified from several databases. We constructed PPI network and screened the core targets according to the degree value. Then, GO and KEGG enrichment were carried out. Molecular docking technology was used to verify the affinity between matrine and the crystal structure of core target protein. Finally, real-time RT-PCR was used to detect the effects of matrine on hub gene expression in liver tissue of liver injury mice and lung tissue of lung injury mice to further confirm the results of network pharmacological analysis. The results show that six core targets including AKT1, TP53, TNF, IL6, BCL2L1 and ATM were identified. The potential therapeutic mechanism of matrine on COVID-19 combined with liver injury is closely related to regulate antiviral process, improve immune system and regulate the level of inflammatory factors. Molecular docking showed that matrine could spontaneously bind to the receptor protein and had strong binding force. Real-time RT-PCR demonstrated that matrine could significantly reduce the expression of AKT1, TP53, TNF, IL6 and ATM in mice with liver injury or lung injury (P < 0.05), and increase the expression of BCL2L1 to a certain extent (P > 0.05). Our results indicate that matrine can achieve simultaneous intervention of COVID-19 combined with liver injury by multi-dimensional pharmacological mechanism.

Objective: Schizophrenia is a mental disorder characterized by reduced social engagement, abnormal emotional expression, and a lack of motivation. Isobaric tags for relative and absolute quantitation (iTRAQ) are a novel proteomic technique. In this study, we intended to identify potential biomarkers for predicting clozapine treatment response using iTRAQ. Methods: We identified patients with schizophrenia that responded to a four-week treatment with clozapine. Patient's peripheral blood mononuclear cells (PBMC) were collected before and after treatment. iTRAQ-based proteomics analysis was done to identify differentially expressed proteins in PBMC before and after treatment. STRING analysis map was built, and a target protein was selected. Western blot validation was then done. Results: In 10 identified clozapine treatment-responsive patients, we screened 2,735 proteins. Nine downregulated proteins and 11 upregulated proteins were differentially expressed by 1.5-fold after clozapine treatment. STRING network analysis revealed a series of apolipoproteins, and only apolipoprotein A4 (APOA-IV) was selected for validation. Western blot validations showed that protein levels of APOA-IV were significantly most downregulated in the patient after clozapine treatment (p = 0.05). Conclusion: In this study, we integrated clinical observation data, bioinformational protein interaction analysis, and iTRAQ labeling to study proteomics in patients with schizophrenia successfully treated with clozapine. We suggest that APOA-IV protein can be a biomarker for predicting clozapine treatment response in patients with schizophrenia. But these results in this study need a larger sample size to be validated.

Drugs are designed and validated based on physicochemical data on their interactions with target proteins. For low water-solubility drugs, however, quantitative analysis is practically impossible without accurate estimation of precipitation. Here we combined quantitative NMR with NMR titration experiments to rigorously quantify the interaction of the low water-solubility drug pimecrolimus with its target protein FKBP12. Notably, the dissociation constants estimated with and without consideration of precipitation differed by more than tenfold. Moreover, the method enabled us to quantitate the FKBP12-pimecrolimus interaction even under a crowded condition established using the protein crowder BSA. Notably, the FKBP12-pimecrolimus interaction was slightly hampered under the crowded environment, which is explained by transient association of BSA with the drug molecules. Collectively, the described method will contribute to both quantifying the binding properties of low water-solubility drugs and to elucidating the drug behavior in complex crowded solutions including living cells.

Protein–membrane interactions play important roles in signal transductions and functional regulation of membrane proteins. Here, we design a molecular dynamometer (MDM) for analyzing protein–membrane interaction on living cells. The MDM is constructed by assembling an artificial lipid bilayer and alkylated Cy3-DNA azide (azide-Cy3-Cx) on a silica bubble. After a functional aptamer is covalently anchored onto the corresponding target protein on a living cell through UV irradiation, azide-Cy3-Cx is conjugated with the aptamer through a click reaction to produce a “tug-of-war” between the MDM and the cell due to the buoyancy of the silica bubble. This induces the detachment of the protein from the cell membrane or the alkane terminal from the MDM enabling sub-piconewton embedding force measurement by changing the alkane chain length and simple fluorescence analysis. The successful analysis of embedding force variation of a protein on the cell membrane upon post-translational modifications demonstrates the practicability and expansibility of this method for mechanics-related research in biological systems., A molecular dynamometer is designed to analyze the variation of sub-piconewton interaction between a specific protein and the membrane on living cells.

Due to their high stability and specificity in living cells, fluorescently labeled nanobodies are perfect probes for visualizing intracellular targets at an endogenous level. However, intrabodies bind unrestrainedly and hence may interfere with the target protein function. Here, we report a strategy to prevent premature binding through the development of photo-conditional intrabodies. Using genetic code expansion, we introduce photocaged amino acids within the nanobody-binding interface, which, after photo-activation, show instantaneous binding of target proteins with high spatiotemporal precision inside living cells. Due to the highly stable binding, light-guided intrabodies offer a versatile platform for downstream imaging and regulation of target proteins.

The development of preventive vaccines became the first order task in the COVID-19 pandemic caused by SARS-CoV-2. This paper reports the construction of the pVAX-RBD plasmid containing the Receptor-Binding Domain (RBD) of the S protein and a unique signal sequence 176 which promotes target protein secretion into the extracellular space thereby increasing the efficiency of humoral immune response activation. A polyglucine-spermidine conjugate (PGS) was used to deliver pVAX-RBD into the cells. The comparative immunogenicity study of the naked pVAX-RBD and pVAX-RBD enclosed in the PGS envelope showed that the latter was more efficient in inducing an immune response in the immunized mice. In particular, RBD-specific antibody titers were shown in ELISA to be no higher than 1 : 1000 in the animals from the pVAX-RBD group and 1 : 42000, in the pVAX-RBD-PGS group. The pVAX-RBD-PGS construct effectively induced cellular immune response. Using ELISpot, it has been demonstrated that splenocytes obtained from the immunized animals effectively produced INF-y in response to stimulation with the S protein-derived peptide pool. The results suggest that the polyglucine-spermidine conjugate-enveloped pVAX-RBD construct may be considered as a promising DNA vaccine against COVID-19.

Cancer is one of the major threats that we face today due to the lack of a proper medicine and its harmful side effects. JAK- STAT pathway has been reported to involve in oncogenesis. Molecules with known JAK2 inhibitory activity were subjected to docking to JAK2 protein using Autodock and Argus lab softwares. The difference in binding energy obtained from both the softwares is due to the difference in parameters used in binding energy calculation. The results show that Autodock outperforms largely ArgusLab in the binding energy correlation with the biological activity. Phytochemicals having anticancer property retrieved from Dr Dukes phytochemical and ethnobotanical database were then docked using Autodock. The phytochemical ajmalimine was identified to have high affinity to the target protein which can be modified to get potent novel JAK2 inhibitors.

Characterizing all possible side effects of compounds is not a trivial task due to unknown off-target proteins that might eventually lead lethal reactions. There is still a tremendous need of computational methods to identify protein targets of a new compound. We have performed a comprehensive analysis for identification of protein targets by integrating tissue-specific protein-protein interaction (PPI) networks and compound induced transcriptome data. Several network centrality metrics are computed to suggest the most probable off-targets of a given compound. The effects of interaction types between proteins and tissue-specific PPI networks are evaluated from multiple perspectives. Usage of network centrality metrics on a tissue-specific PPI network enhances the correct prediction rate of known targets of a given compound. The detailed analysis of successfully identified known targets indicated that degree and local radiality metrics are more practical for determining different types of target protein families, such as GPCR, chemokines, proteasome, and protein kinase families. Therefore, the proposed computational pipeline is applicable while investigating proteins from these families that can be especially targeted for treatment of complex diseases. To the best of our knowledge, this study for the first time presents how tissue-specific transcriptome changes alter the topological structure of PPI networks and the relative effects of tissue-specific networks in target identification. Overall, the proposed computational methods are practical tools for choosing more accurate protein targets for later computational analysis and wet-lab experiments.

Lipoic acid is an essential cofactor produced in all organisms by diverting octanoic acid derived as an intermediate of type II fatty acid biosynthesis. In bacteria, octanoic acid is transferred from the acyl carrier protein (ACP) to the lipoylated target protein by the octanoyltransferase LipB. LipB has a well-documented substrate selectivity, indicating a mechanism of octanoic acid recognition. The present study reveals the precise protein–protein interactions (PPIs) responsible for this selectivity in Escherichia coli through a combination of solution-state protein NMR titration with high-resolution docking of the experimentally examined substrates. We examine the structural changes of substrate-bound ACP and determine the precise geometry of the LipB interface. Thermodynamic effects from varying substrates were observed by NMR, and steric occlusion of docked models indicates how LipB interprets proper substrate identity via allosteric binding. This study provides a model for elucidating how substrate identity is transferred through the ACP structure to regulate activity in octanoyl transferases., Lipoic acid, an essential cofactor produced in all organisms, diverts octanoic acid from type II fatty acid biosynthesis through a highly specific protein–protein interaction. This study characterizes how different substrates influence this interface to control chain length specificity.

Graphical abstract, Highlights • Evolutionary design of new SARS-CoV-2 spike proteins by perturbing the core protein sequence without changing the surface conformation. • Computationally designed SARS-CoV-2 spike proteins contain additional MHC-II T cell promiscuous epitopes with enhanced T cell immunity. • Structurally designed SARS-CoV-2 spike proteins preserve function and B cell immunity. • The newly designed SARS-CoV-2 spike proteins can be explored as new COVID-19 vaccine candidates., The development of effective and safe vaccines is the ultimate way to efficiently stop the ongoing COVID-19 pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Built on the fact that SARS-CoV-2 utilizes the association of its Spike (S) protein with the human Angiotensin-converting enzyme 2 (ACE2) receptor to invade host cells, we computationally redesigned the S protein sequence to improve its immunogenicity and antigenicity. Toward this purpose, we extended an evolutionary protein design algorithm, EvoDesign, to create thousands of stable S protein variants that perturb the core protein sequence but keep the surface conformation and B cell epitopes. The T cell epitope content and similarity scores of the perturbed sequences were calculated and evaluated. Out of 22,914 designs with favorable stability energy, 301 candidates contained at least two pre-existing immunity-related epitopes and had promising immunogenic potential. The benchmark tests showed that, although the epitope restraints were not included in the scoring function of EvoDesign, the top S protein design successfully recovered 31 out of the 32 major histocompatibility complex (MHC) -II T cell promiscuous epitopes in the native S protein, where two epitopes were present in all seven human coronaviruses. Moreover, the newly designed S protein introduced nine new MHC-II T cell promiscuous epitopes that do not exist in the wildtype SARS-CoV-2. These results demonstrated a new and effective avenue to enhance a target protein’s immunogenicity using rational protein design, which could be applied for new vaccine design against COVID-19 and other human viruses.

A variety of butan-2-ylidene benzohydrazides were synthesized via the reaction of benzohydrazides with 4,4,4-triflouro-1-phenyl-1,-3-butanedione/4,4,4 – triflouro -1, 2, - (2 – napthyl) -1, 3 – butanedione. Acetylation and benzoylation of butan-2-ylidene benzohydrazides gave the derivatives previously unknown. The compounds were characterized by spectral analyses (Mass spec., IR, and NMR), and were evaluated for their in vitro antimicrobial activity against some clinical isolates of interest. The in vitro screening revealed that some of the compounds possessed strong inhibitory potentials against the isolates with IZD in the range of 7-14 mm. Predicted ADMET ensured the druggability properties of the synthesized compounds. The molecular docking study indicated compounds7a and 9a to possess the highest docking store and established significant interactions in the active site of the target protein.

A novel series of 1,2,3-triazolyl-pyridine hybrids were prepared through the reaction of the triazole derivative (1) with the appropriate aldehyde (2a-g) and malononitrile or ethyl cyanoacetate in the presence of ammonium acetate in refluxed acetic acid. The chemical composition of the products was established on the basis of spectral and elemental analyses. Aurora B kinase is a protein with diverse biological actions in controlling tumorigenesis by inhibiting apoptosis and promoting proliferation and metastasis, making it an emerging target for diseases such as hepatocellular carcinoma (HCC). Alteration in the target protein expression causes unequal distribution of genetic information, causing HCC. The new compounds were tested for their antihepatic cancer activity, and some of them had strong efficacy against human hepatoblastoma (HepG2) cell lines.

Proteins are typically separated by an immune reaction, such as an enzyme-linked immunosorbent assay, and are detected by selective fluorescent labeling. This has potential for complicated procedures and the denaturation of proteins by labeling, and is cost consuming. In this study, we propose a technique for the selective separation and detection of a target protein using a molecularly imprinted hydrogel (PI gel) with fluorescent monomers. We focused on 8-anilino-1-naphthalenesulfonic acid (ANS), where the fluorescence intensity is easily changed by the interaction with proteins, and successfully synthesized the ANS monomer and a poly(ethylene glycol) (PEG) conjugated ANS monomer. The PI gel with the ANS monomers using bovine serum albumin (BSA) as a template showed the selective adsorption of BSA and the fluorescence intensity increased due to the adsorption of BSA.

Epitope molecularly imprinted polymers (EMIPs) are novel imprinted materials using short characteristic peptides as templates rather than entire proteins. To be specific, the amino acid sequence of the template peptide is the same as an exposed N- or C-terminus of a target protein, or its amino acid composition and sequence replicate a similar conformational arrangement as the same amino acid residues on the surface of the target protein. EMIPs have a good application prospect in protein research. Herein, we focus on classification of epitope imprinting techniques, methods of epitope immobilization on matrix materials including boronate affinity immobilization, covalent bonding immobilization, physical adsorption immobilization and metal ion chelation immobilization, and application of EMIPs in peptides, proteins, target imaging and target therapy fields. Finally, the main problems and future development are summarized.

The severe acute respiratory syndrome coronavirus, identified as SARS-CoV-2, initially established in Wuhan, China at the end of 2019, affects respiratory infections known as COVID-19. In an extraordinary manner, COVID-19 is affecting human life and has transformed a global public health issue into a crisis. Natural products are already recognized owing to the massive advantageous window and efficient antioxidant, antiviral immunomodulatory, and anti-inflammatory belongings. Additionally, the object of the present study was to demonstrate the inhibitory potential of the natural products coumarins and its analogues alongside SARS coronavirus. The present work, focuses on the synthesis of new coumarin analogues and characterized by FT-IR, 1H and 13C NMR, elemental analyses, and mass spectra. The recently synthesised compounds were projected conceptual association for COVID-19 protease and also to explore in anticipation if this protein will help target protease inhibitor drugs such as Calanolide A, Cardatolide A, Collinin, Inophyllum A, Mesuol, Isomesuol, Pteryxin, Rutamarin, Seselin and Suksdorin. The natural coumarin analogues docking scores were compared to standard Hydroxychloroquine. While the 3D module of SARS coronavirus main protease was predicted with the SWISS MODEL web server, as well as biochemical interaction tests were performed with the AutoDock Vina tool between the target protein with ligands. This research further showed that all the protease inhibitors accessed the target protein with negative dock energy. Molecular docking studies found that the natural coumarin analogue Inophyllum A showed an exceptional potential for inhibition with a binding energy of −8.4 kcal/mol. The synthetic coumarin analogues 1m and 1p both demonstrated a similar binding energy, inhibition potential of −7.9 kcal / mol as opposed to hydroxychloroquine and co-crystallized ligand alpha-ketoamide with binding energy values of −5.8 and −6.6 kcal / mol. All compounds evaluated were known as drug-like in nature, passing Lipinski's “Law of 5” with 0 violations except for alpha-ketoamide, passing Lipinski's “Rule of 5” with 1 violation (MW > 500). The inhibitor binding in silico research thus offers a structural understanding of COVID-19 and molecular interactions across the known protease inhibitors centred on the findings of the multiple sequence alliance.