Abstract: Three psychrophilic protein pheromones (En-1, En-2 and En-6) from the polar ciliate, Euplotes nobilii, and six mesophilic pheromones (Er-1, Er-2, Er-10, Er-11, Er-22 and Er-23) from the temperate-water sister species, Euplotes raikovi, were studied in aqueous solution for their thermal unfolding and refolding based on the temperature dependence of their circular dichroism (CD) spectra. The three psychrophilic proteins showed thermal unfolding with mid points in the temperature range 55–70 °C. In contrast, no unfolding was observed for any of the six mesophilic proteins and their regular secondary structures were maintained up to 95 °C. Possible causes of these differences are discussed based on comparisons of the NMR structures of the nine proteins.
Keywords: protein denaturation; protein stability; circular dichroism spectroscopy; psychrophilic proteins; chemical signals
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Geralt, M.; Alimenti, C.; Vallesi, A.; Luporini, P.; Wüthrich, K. Thermodynamic Stability of Psychrophilic and Mesophilic Pheromones of the Protozoan Ciliate Euplotes. Biology 2013, 2, 142-150.
Geralt M, Alimenti C, Vallesi A, Luporini P, Wüthrich K. Thermodynamic Stability of Psychrophilic and Mesophilic Pheromones of the Protozoan Ciliate Euplotes. Biology. 2013; 2(1):142-150.
Geralt, Michael; Alimenti, Claudio; Vallesi, Adriana; Luporini, Pierangelo; Wüthrich, Kurt. 2013. "Thermodynamic Stability of Psychrophilic and Mesophilic Pheromones of the Protozoan Ciliate Euplotes." Biology 2, no. 1: 142-150.