ABSTRACT
Every organism, regardless of its optimal growth temperature, has to deal with the issue of thermal stability (both physical and functional) of its cell components. This statement is probably more patent in the case of proteins, entities that have to maintain a certain degree of fl exibility to remain functional; therefore, the balance between stability and fl exibility is a central feature in protein architecture [3-6]. This compromise has to be adapted to the environmental conditions in which each organism lives, namely temperature. In the case of thermophiles and hyperthermophiles
[from this point on denominated as (hyper)thermophiles], proteins tend to display a higher intrinsic stability and are therefore assumed to have a lower fl exibility, in other words, (hyper)thermophilic proteins would be more rigid to achieve a higher stability [7].
