The emergence of multiple drug‐resistant “super gonorrhoea” complicates the management and treatment of Neisseria gonorrhoeae infections due to the progressive accumulation of mutations in the biological targets of frontline antimicrobials. Continuous evaluation and reporting of newer molecular targets and their inhibitors are necessary. Here, we present l‐asparaginase of N. gonorrhoeae (NgA) as a new molecular target based on structure‐based high‐throughput screening, molecular dynamics(MD) simulations, and validation by biophysical, biochemical, and cell viability assays. We observed that the NgA is evolutionarily conserved in both the drug‐resistant and susceptible strains of N. gonorrhoeae, indicating its importance in the growth and survival of the pathogen. Three Food and Drug Administration‐approved drugs, pemirolast, thalidomide, and decitabine, were identified as potential inhibitors of NgA using high‐throughput screening. The binding energies of the drugs with NgA were −20.14, −19.67, and −16.47 kcal/mol, respectively, compared to −6.82 ± 1.46 for enzyme–substrate l‐Asn, as obtained through MD simulations. Subsequently, fluorescence quenching and differential scanning calorimetry experiments validated the in silico data. The observance of inhibition of NgA activity at micromolar drug concentrations further strengthened our findings. Conclusive evidence came from the cell viability assays where these drugs were found to impede the growth of N. gonorrhoeae culture effectively. Thus, our study establishes l‐asparaginase as a new molecular target against gonococcal infections. From this study, we propose that targeting of NgA can be explored to control N. gonorrhoeae infections in combination therapy.

The receptor binding domain(s) (RBD) of spike (S) proteins of SARS-CoV-1 and SARS-CoV-2 (severe acute respiratory syndrome coronavirus) undergoes closed to open transition to engage with host ACE2 receptors. In this study, using multi atomistic (equilibrium) and targeted (non-equilibrium) molecular dynamics simulations, we have compared energetics of RBD opening pathways in full-length (modeled from cryo-EM structures) S proteins of SARS-CoV-1 and SARS-CoV-2. Our data indicate that amino acid variations at the RBD interaction interface can culminate into distinct free energy landscapes of RBD opening in these S proteins. We further report that mutations in the S protein of SARS-CoV-2 variants of concern can reduce the protein–protein interaction affinity of RBD(s) with its neighboring domains and could favor its opening to access ACE2 receptors. The findings can also aid in predicting the impact of future mutations on the rate of S protein opening for rapid host receptor scanning.

Background Visceral Leishmaniasis (VL) is a fatal vector-borne parasitic disorder occurring mainly in tropical and subtropical regions. VL falls under the category of neglected tropical diseases with growing drug resistance and lacking a licensed vaccine. Conventional vaccine synthesis techniques are often very laborious and challenging. With the advancement of bioinformatics and its application in immunology, it is now more convenient to design multi-epitope vaccines comprising predicted immuno-dominant epitopes of multiple antigenic proteins. We have chosen four antigenic proteins of Leishmania donovani and identified their T-cell and B-cell epitopes, utilizing those for in-silico chimeric vaccine designing. The various physicochemical characteristics of the vaccine have been explored and the tertiary structure of the chimeric construct is predicted to perform docking studies and molecular dynamics simulations. Results The vaccine construct is generated by joining the epitopes with specific linkers. The predicted tertiary structure of the vaccine has been found to be valid and docking studies reveal the construct shows a high affinity towards the TLR-4 receptor. Population coverage analysis shows the vaccine can be effective on the majority of the world population. In-silico immune simulation studies confirms the vaccine to raise a pro-inflammatory response with the proliferation of activated T and B cells. In-silico codon optimization and cloning of the vaccine nucleic acid sequence have also been achieved in the pET28a vector. Conclusion The above bioinformatics data support that the construct may act as a potential vaccine. Further wet lab synthesis of the vaccine and in vivo works has to be undertaken in animal model to confirm vaccine potency.

Parkinson’s disease (PD) is the second most common neurodegenerative disease. The presence of lewy bodies, primarily consisting of α-synuclein (α-syn) aggregates is one of the common features seen in the substantia nigra region of the brain in PD patients. The disease remains incurable and only symptomatic relief is available. We screened various cell-penetrating peptides and reveal that penetratin is a potent inhibitor of α-syn aggregation in-vitro, and significantly improved locomotor coordination in mice models of PD in-vivo. The peptide inhibits α-syn aggregation in vitro as well as in yeast, and C.elegans models. We further made a cyclic derivative of penetratin by disulfide coupling of N- and C-terminal cysteine residues. Both penetratin and its cyclized derivative interact with α-syn. NMR studies show that both linear as well as cyclic derivative interact at the acidic C-terminal tail of the protein. Similar to penetratin, its cyclic derivative inhibited α-syn aggregation in the C.elegans model of Parkinson’s disease, and also improved worm motility. Molecular Dynamics studies show that penetratin interacts with α-synuclein and prevents its conformational transition from disordered into β-sheet rich structure. The therapeutic efficacy of penetratin was further confirmed in a transgenic mice model of the disease, wherein penetratin treatment over a period of 90 days improved locomotor coordination, and halted disease progression. Overall, the present work provides a potent therapeutic agent that could be further explored in the management of PD.

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