Assisted protein folding at low temperature: evolutionary adaptation of the Antarctic fish chaperonin CCT and its client proteins

Biology Open

Jorge Cuellar¹  Marina Serna¹  José María Valpuesta¹  Hugo Yébenes¹  Juan Carlos Zabala²  Gerardo Carranza²  Sandra K. Parker³  H. William Detrich³ 

[1] Centro Nacional de Biotechnología (CNB-CSIC), Campus de la Universidad Autónoma de Madrid, 28049 Madrid, Spain;Departamento de Biología Molecular, Universidad de Cantabria-IFIMAV, 39011 Santander, Spain;Department of Marine and Environmental Sciences and Department of Biology, Northeastern University, Marine Science Center, Nahant, MA 01908, USA;

关键词: CCT;    TriC;    Chaperone;    Chaperonin;    Protein folding;    Actin;    Tubulin;    Thermal adaptation;    Evolution;   

DOI  :  10.1242/bio.20147427

来源: DOAJ

【 摘 要 】

Eukaryotic ectotherms of the Southern Ocean face energetic challenges to protein folding assisted by the cytosolic chaperonin CCT. We hypothesize that CCT and its client proteins (CPs) have co-evolved molecular adaptations that facilitate CCT–CP interaction and the ATP-driven folding cycle at low temperature. To test this hypothesis, we compared the functional and structural properties of CCT–CP systems from testis tissues of an Antarctic fish, Gobionotothen gibberifrons (Lönnberg) (habitat/body T = −1.9 to +2°C), and of the cow (body T = 37°C). We examined the temperature dependence of the binding of denatured CPs (β-actin, β-tubulin) by fish and bovine CCTs, both in homologous and heterologous combinations and at temperatures between −4°C and 20°C, in a buffer conducive to binding of the denatured CP to the open conformation of CCT. In homologous combination, the percentage of G. gibberifrons CCT bound to CP declined linearly with increasing temperature, whereas the converse was true for bovine CCT. Binding of CCT to heterologous CPs was low, irrespective of temperature. When reactions were supplemented with ATP, G. gibberifrons CCT catalyzed the folding and release of actin at 2°C. The ATPase activity of apo-CCT from G. gibberifrons at 4°C was ∼2.5-fold greater than that of apo-bovine CCT, whereas equivalent activities were observed at 20°C. Based on these results, we conclude that the catalytic folding cycle of CCT from Antarctic fishes is partially compensated at their habitat temperature, probably by means of enhanced CP-binding affinity and increased flexibility of the CCT subunits.

【 授权许可】

Unknown