A three dimensional theoretical model of SP1 (stable protein 1), which is resistant to high temperature and biotic-stresses, is presented here. The model was generated by the application of homology modeling technique. The conformational rigidity imparted to the fold by the presence of hydrogen-bonded, C₅, C₇, C₁₀ and C₁₃ structures in the loop regions, multiple aromatic ? aromatic interactions at the protein interior and on the surface, in addition to salt-links and hydrogen-bonds are primarily the major factors, responsible for the increased stability of protein. The putative protein family is characterized by motifs, E-x(0,1)-L-x-[AEGQS] and V-x(2,3)-L-x-[ADEGST] and the active site in the tertiary structure is formed by conserved aromatic and isoleucine clusters.

Key words: Thermostability, Thermophilic, SP1, Aromatic clusters, Homology modeling.