Computational and Synthetic Biology Approaches for the Biosynthesis of Antiviral and Anticancer Terpenoids from Bacillus subtilis.

Recent advancements in medicinal research have identified several antiviral and anticancer terpenoids that are usually deployed as a source of flavor, fragrances and pharmaceuticals. Under the current COVID-19 pandemic conditions, natural therapeutics with the least side effects are the need of the hour to save the patients, especially, which are pre-affected with other medical complications. Although plants are the major sources of terpenoids; however, for the environmental concerns, the global interest has shifted to the biocatalytic production of molecules from microbial sources. The gram-positive bacterium Bacillus subtilis is a suitable host in this regard due to its GRAS (generally regarded as safe) status, ease in genetic manipulations and wide industrial acceptability. The B. subtilis synthesizes its terpenoid molecules from 1-deoxy-d-xylulose-5-phosphate (DXP) pathway, a common route in almost all microbial strains. Here, we summarize the computational and synthetic biology approaches to improve the production of terpenoid-based therapeutics from B. subtilis by utilizing DXP pathway. We focus on the in-silico approaches for screening the functionally improved enzyme-variants of the two crucial enzymes namely, the DXP synthase (DXS) and Farnesyl Pyrophosphate Synthase (FPPS). The approaches for engineering the active sites are subsequently explained. It will be helpful to construct the functionally improved enzymes for the high-yield production of terpenoid-based anticancer and antiviral metabolites, which would help to reduce the cost and improve the availability of such therapeutics for the humankind.

Exploration of the binding modes of L-asparaginase complexed with its amino acid substrates by molecular docking, dynamics and simulation.

Acute lymphocytic leukemia (ALL) is an outrageous disease worldwide. L-Asparagine (L-Asn) and L-glutamine (L-Gln) deamination plays crucial role in ALL treatment. Role of Erwinaze® (L-asparaginase from Erwinia chrysanthemi) in regulation of L-Asn and L-Gln has been confirmed by the experimental studies. Therapeutic research against ALL remained elusive with the lack of structural information on Erwinaze® enzyme. In this present study, homology model of the Erwinaze® was developed using MODELLER and the same was validated by various quality indexing tools. For the apo state enzyme and ligand bound state complexes molecular dynamics (MD) simulation was performed. The trajectory analysis showed the confirmational changes of structures in the dynamic system. Ligand binding mechanisms were studied using different docking tools to interpret the various ligand-receptor interactions and binding free energies. MD simulation of docked complex with L-Gln ligand substrate showed the defined structural folding with stable conformation over the L-Asn complex in dynamic environment. This research reports give much more information on structural and functional aspects of Erwinaze® with its ligands which may be useful in designing of effective therapeutics for ALL.