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In the present investigation, a novel thermophilic L-asparaginase (Asn_PA) from Pseudomonas aeruginosaCSPS4 was investigated to explore its structural insights at elevated temperatures. Sequence analysis of Asn_PA depicted three conserved motifs (VVILATGGTIAG, DGIVITHGTDTLEETAYFL, and, LRKQGVQIIRSSHVNAGGF), of them, two motifs exhibit catalytically-important residues i.e., T45and T125. A homology modelling-based structure model for Asn_PA was generated with 4PGA as the top-matched template. The predicted structure was validated and energy was minimized. Molecular docking was carried out cantered at the active site for asparagine and glutamine as its substrate ligands. The enzyme–substrate interaction analysis showed binding affinities of  – 4.8 and  – 4.1 kcal/mol for asparagine and glutamine respectively. Molecular dynamics (MD) simulation studies showed a better stability of Asn_PA at temperatures of 60 °C, over 40, 50 and, 80 °C, making this enzyme a novel L-asparaginase from other mesophilic P. aeruginosastrain. The trajectory analysis showed that RMSD, Rg, and, SASA values correlate well with each other in the different tested temperatures during the MD analysis. Thus, the present findings encourage extensive characterization of the Asn_PA using laboratory experiments to understand the structural behavior of the active site loop in an open or closed state with and without the substrate molecules.

In this review, we discuss the synthetic approaches to γ-amino-β-hydroxybutyric acid (GABOB) and carnitine from 1980 to date. The unique structure and biological importance of these molecules have created much interest in various synthetic approaches over the last four decades by organic chemists from across the world. Most of the syntheses are asymmetric methods that involved chiral pool, enantioselective synthesis, enzyme resolution, or a chiral auxiliary as a source of chirality, and the biological significance of the molecules was also discussed. The compiled synthetic methods may fill the existence gap, simplify the complexity involved in the synthesis, and allow the best synthetic route to be found by comparison of all the methods. However, this review also will be useful to prepare similar kind of scaffolds present in various complex natural products.