An archaeal chaperonin-based reactor for renaturation of denatured proteins

We describe an original chaperonin-based reactor that yields folded and act ive proteins from denatured materials. We used the 920-kDa chaperonin of th e archaeon Sulfolobus solfataricus, which does not require any protein part ner for its full activity and assists in vitro folding with low substrate s pecificity. The reactor consists of an ultrafiltration cell equipped with a membrane that retains the chaperonin in a functional state for folding in solution and permits the flowthrough of the folded substrates. By studying the ATP-dependent functional cycle of the chaperonin, we were able to use t he reactor for repeated refolding processes. The scale-up of the reactor is made possible by the overproduction of chaperonin in Sulfolobus solfataric us cells that acquired thermotolerance upon appropriate heat shock.