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

• DOI: 10.1242/bio.20147427
• Publication Date: 2014-03-22T04:14:59Z
• Authors: Jorge Cuellar; Hugo Yébenes; Sandra K. Parker; Gerardo Carranza; Marina Serna; José María Valpuesta; Juan Carlos Zabala; H. William Detrich
• Keywords: Chaperonin; Heterologous; Ectotherm; Chaperone (clinical)

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