Introduction: Understanding the factors responsible for enzyme thermostability and discriminating them from mesophilic proteins is one of the most important concerns in engineering new proteins. The primary structure of a protein is an important factor in determining L-asparaginase thermostability and it can be improved by adjusting external environmental factors. L-asparaginase II possesses antitumor activity and expressed in the periplasmic space of the bacterial membranes as it catalyzes the conversion of L-asparagine to L-aspartic acid
Methods: In present study, in silico analysis of amino acid sequences of ten mesophilic and ten thermophilic bacterial L-asparaginases has been done. The sequences were subjected to multiple sequence alignment (MSA), discovering individual amino acid composition, and phylogenetic tree construction.
Results: The multiple sequence alignment analysis of amino acid sequences has shown clear differences between mesophilic and thermophillic asparaginases in terms of position specific presence of conserved amino acids. The physiochemical properties of these two groups of L-asparaginase enzyme also differ in number of amino acids, molecular weight, positively charged ions, i.e. Arg + Lys, aliphatic index, Grand Average of Hydropathacity (GRAVY) and the compositions of different amino acid residues. The comparative study of amino acid sequence and physicochemical properties indicate the affiliation of protein from L-asparaginase enzyme of nitrilase superfamily.
Conclusion: The present finding will be helpful in identification and elucidation of the extent of thermostability among Lasparaginases from the large number of sequenced microbial genomes for current as well as future biotechnological applications.
Keywords: L-Asparaginase, Mesophile, Multiple sequence alignment, Thermophile, Thermostability, Phylogenetic tree.