Trehalose radial networks protect Renilla luciferase helical layers against thermal inactivation

Renilla luciferase (Rluc) from Renilla reniformis is an appropriate protein reporter for the detection of specific molecular targets due to its bioluminescent feature, although its relatively low stability limits the application. To investigate the effects of trehalose and sucrose as chemical chaperones on the kinetic stability of Rluc, we assayed the activity of the enzyme in the presence of these additives at high temperatures and to comprehend the mechanism of stability, molecular dynamic (MD) simulation was carried out. In the presence of trehalose a thermostabilizing effect which was considerable in comparison with other systems was observed. It is proposed that a wide radial like network of trehalose molecules supports α-helix structures that are located in the N-terminus and C-terminus of the protein. However, in the water simulation box, these helices alter to instable structures at high temperatures. Reduction of the fluctuation of these helices in the presence of trehalose molecules, may prevent the protein from unfolding and increase its shelf life.