Investigating the Mechanism by which Cosolvents Stabilize Protein Structure

Proteins can be stabilized with the use of osmolytes, small soluble compounds such as sugars found in nature. This study explores the fundamental relationship between protein stability in a sugar, the incubation time, and thermophilic or mesophilic nature of the protein. Two DNA photolyases, Sulfolobus sulfataricus (thermophile) and E-coli (mesophile), were analyzed using a buffer with 0.55 M trehalose and 0.20 M β-glycerol phosphate. The thermostability of the thermophile was measured at 65 oC while the mesophile was measured at 45oC, and the half-lives of the proteins were quantified. The incubation time of the thermophile in the buffer prior to heating was crucial to the thermostability of the protein. No such effect was observed with the mesophile.