Summary

The existence of Life has been reported from every nook and corner of this world whether itís a deep sea or hot spring. These extremophilic microorganisms have evolved variety of mechanisms to combat with the survival conditions and adapted accordingly. Researchers have reported various clues for their stability at extreme conditions such uniqueness in membrane lipid composition, higher turn over rates of thermostable enzymes etc. But no specific reason has been identified by researchers till date which can satisfy this structural stability.

The present research work is an attempt to investigate in detail the structural adaptation in extremophilic protein in relation to secondary structure elements. The availability of structures is again a major constraint in boosting such structure based evolutionary research. However, for present investigation 106 structures of five vital enzymes of glycolytic pathway from four different temperature classes (Hyperthermophiles, Thermophiles, Mesophiles and Psychrophiles) were chosen as dataset and a computation analysis was performed in order to explore the trend of structural adaptability through comparative analysis.

In the present study it has been identified that the average percentage ratio of helix to sheet was approximately 75:25 for all extremophilic groups which indicate that nature use some definite mechanism in allocating the secondary structure elements (SSEs) as structural components in extremophilic proteins which allows these proteins to conform into specific geometrical arrangement using SSEs and hence stabilize the molecule accordingly.

A higher degree of variation in residual composition was observed in mesophiles and psychrophiles as compared to thermophiles and hyperthermophile which suggest that at higher temperature the hydrophobic core of extremophilic proteins tend to be conserved and shows less variation in composition.

Hence it can be concluded that these extremophilic microorganisms have evolved independent mechanism for structural stability and undergoes various structural adaptations at different survival conditions