Several sequence and structural features have been hypothesised to contribute to the more excellent stability of thermophilic proteins. This study aims to compare the protein sequence of protease based on the difference of their thermostability and to identify the selected interaction between amino acids in a three-dimensional structure with different thermostability of thermostable alkaline protease 50a (TAP 50a). Results from CL USTALW to get the multiple sequence alignment showed the conservation of amino acids. PyMol was used to analyse the inter-intramolecular interactions of the TAP 50a structure and the amino acid residues for the a-helices, 13-sheets, and loops. Thermostable alkaline protease 50a (TAP 50a) comprises 255 amino acid residues with a calculated molecular weight of 25 kDa and an isoelectric point of 6.04. The amino acid sequence indicates that this protease consists of a mature protein. Ion-pairs are generated by 1.6% of Arg residues, 2.4% of His residues, 3.5% of Asp residues and 2.0% of Lys residues. Contrary to this, a considerable fraction of oppositely charged pairings is separated by lengths less than six microns. TAP 50a of bacillus subtilis sp. produces a thermostable protease with a 25kDa protease with a pH optimum of 5.9 and a half-life of 3 hours 40 mins at 80°C. The less distance between amino acid residues, the higher the thermostability of the protease enzyme. This study may help identify the thermostability of proteases by analysing the 3D structure and the enzyme contribution factors.
Keywords: TAP 50a, amino acid sequences, multiple sequence alignment,
intermolecular interaction, three-dimensional structure