Genome-wide detection of terpene synthase genes in holy basil (Ocimum sanctum L.).

Holy basil (Ocimum sanctum L.) and sweet basil (Ocimum basilicum L.) are the most commonly grown basil species in India for essential oil production and biosynthesis of potentially volatile and non-volatile phytomolecules with commercial significance. The aroma, flavor and pharmaceutical value of Ocimum species is a significance of its essential oil, which contains most of the monoterpenes and sesquiterpenes. A large number of plants have been studied for characterization and identification of terpene synthase genes, involved in terpenoids biosynthesis. The goal of this study is to discover and identify the putative functional terpene synthase genes in O. sanctum. HMMER search was performed by using a set of 13 well sequenced and annotated plant genomes including the newly sequenced genome of O. sanctum with Pfam-A database locally, using HMMER 3.0 hmmsearch for the two Pfam domains (PF01397 and PF03936). Using this search method 81 putative terpene synthases genes (OsaTPS) were identified in O. sanctum; the study further reveals 47 OsaTPS were putatively functional genes, 19 partial OsaTPS, and 15 OsaTPS as probably pseudogenes. All these identified OsaTPS genes were compared with other plant species, and phylogenetic analysis reveals the subfamily classification of OsaTPS in TPS-a, -b, -c, -e, -f and TPS-g subfamilies clusters. This genome-wide identification of OsaTPS genes, their phylogenetic analysis and secondary metabolite pathway mapping predictions together provide a comprehensive understanding of the TPS gene family in Ocimum sanctum and offer opportunities for the characterization and functional validation of numbers of terpene synthase genes.

In silico modelling and molecular dynamics simulation studies on L-Asparaginase isolated from bacterial endophyte of Ocimum tenuiflorum.

Bioactive compounds from endophytes have been used to treat various diseases. In the present study, L-Asparaginase producing endophytes were isolated from Ocimum tenuiflorum (Tulasi) from NIT Warangal, Telangana, India to treat Acute Lymphoblastic Leukemia (ALL) in which L-Asparagine (L-Asn) deamination plays a vital role in ALL treatment. 20 (bacteria and fungi) out of 35 endophytes have been screened for L-Asparaginase production using rapid plate assay technique, in which four strains produced high amounts of L-Asparaginase. 16 s Ribosomal RNA sequencing studies were performed, Bacillus stratosphericus organism was identified, and purified L-Asparaginase sequence has been tailored using MALDI/TOF (Applied Biosystems). The homology model was developed by using MODELLER 9.15v as the endophyte lacks crystal structure of L-Asparaginase enzyme and validated by dint of quality index tools. Docking studies were performed using iGemdock 2.1v. In comparison, free energy binding efficiency of receptor towards L-Asparagine (L-Asn) is good with lesser energy -71.6 kcal/mol in comparison to L-Glutamine (L-Gln) having -67.7 kcal/mol. In order to find the stability of the docked complexes in dynamics environment, molecular dynamics and simulation studies were performed using GROMACS V4.6.5. The trajectory analysis for 10 ns shows the better RMSD, RMSF, Rg and average number of hydrogen bonds for complex 1 (L-Asparaginase + L-Asn docked complex). Hence, complex 1 was found to be more stable than Complex 2 (L-Asparaginase + L-Gln docked complex).