Prevention of in Vitro Thermal Aggregation and Inactivation of Foreign Proteins by the Hyperthermophilic Group II Chaperonin α-Subunit from Aeropyrum pernix K1

In this study, we report that the recombinant α subunit chaperonin protein (ApCpnA) from Aeropyrum pernix K1 can efficiently prevent the thermal aggregation and inactivation of foreign model proteins, such as citrate synthase (CS) from= porcine heart, alcohol dehydrogenase (ADH) from Saccharomyces cerevisiae (four 37.5 kDa subunits), and malate dehydrogenase (MDH) from Thermus flavus (two 67 kDa subunits)K=In the presence of ApCpnA and ATP, the thermal aggregation of CS and ADH were prevented by 90 and 65%, respectively, at each 43 and 50°C. Also, the activities of CS, ADH, and MDH under the thermal inactivation conditions were stably maintained at higher than 80% by addition of ApCpnA and ATP, while the activities of those enzymes in the absence of ApCpnA and ATP were dramatically inactivated and decreased below 20% within 30 min. Based on these results, we propose that the α subunit chaperonin from the hyperthermophilic archaeon, A. pernix K1 can be utilized to enhance the durability and cost effectiveness of high-temperature biocatalysts.