Mechanism of thermal aggregation of yeast alcohol dehydrogenase I: Role of intramolecular chaperone

Kinetics of thermal aggregation of yeast alcohol dehydrogenase I (yADH) have been studied using dynamic light scattering at a fixed temperature (56 °C) and under the conditions where the temperature was elevated at a constant rate (1 K/min). The initial parts of the dependences of the hydrodynamic radius on time (or temperature) follow the exponential law. At rather high values of time splitting of the population of aggregates into two components occurs. It is assumed that such peculiarities of the kinetics of thermal aggregation of yADH are due to the presence of a sequence –YSGVCHTDLHAWHGDWPLPVK– in the polypeptide chain possessing chaperone-like activity. Thermodynamic parameters for thermal denaturation of yADH have been calculated from the differential scanning calorimetry data.