IN SILICO CHARACTERIZATION OF HUMAN TYROSINASE USING COMPUTATIONAL TOOLS AND SERVERS

Abstract

In this paper, sequences of six human tyrosinase, retrieved from Swiss Prot database are analyzed and characterized using In silico tools. Primary structure analysis shows that most of the tyrosinase are hydrophobic in nature due to the high content of non -polar residues. The presence of cysteines in the most of the tyrosinases sequences infer that these proteins may form disulphide (SS) bonds, which are regarded as a positive factor for stability. The aliphatic index computed by Ex-Pasy’s ProtParam infers that tyrosinases may be thermolabile for a wide range of temperature. Secondary structure analysis shows that some of the tyrosinases have predominant α-helical structures and rest of the tyrosinases have mixed secondary structure. The very high coil structural content of most of the sequences is due to the rich content of more flexible glycine and hydrophobic proline amino acids. Proline has a special property of creating kinks in polypeptide chains and disrupting ordered secondary structure. The number of cleaveges and the site of cleavage of the enzyme chymotrypsin and trypsin is calculated by the Ex-Pasy’s peptide cutter tool for all the six sequences of tyrosinase.SOSUI server predicts  transmembrane regions in P14679, P40126, P17643, Q04671and P21583 tyrosinases. EMBOSS pepwheel is used for generating helical wheel plot from the predicted transmembrane region.The presence of disulphide (SS) bonds in the tyrosinases P98187, P14679, P40126, P17643, Q04671, 075030 and P21583 are predicted by CYS_REC tool, and the homology model of P14679 is visualized using Rasmol & Swiss-Pdb Viewer (SPDBV) tools. Homology model of P14679 is good as the evaluation parameters are within the acceptable limits for the modeled 3D structures.