A chaperone, thermosome (THS), from the archaea Thermoplasma acidophilum, assists the folding of other macromolecular structures. THS is sphere protein cage, approximately 16 nm in diameter, consisting of two hemispheres that are both assembled from eight subunits. We have genetically engineered the THS to display cysteine residues on the wall of its cavity. They serve as selective attachment points that allow us to encapsulate proteins, catalysts, polymers and other guests within the THS. The surface of the THS can be further modified, e.g. with targeting ligands for controlled drug-delivery purposes.

In our group, we use THS as a nanoreactor and as a nanocarrier for drugs. The former will be highlighted here: THS was used as a nanoreactor for the synthesis of polymers via ATRP (atom transfer radical polymerization) by attaching an ATRP-catalyst within the cavity. The cavity represents a confined reaction space that favourably influenced ATRP. Polymers synthesized within THS possess a narrower polydispersity than polymers synthesized without the nanoreactor. Polymerization within the THS could become a means to study and control the folding of single polymer chains.

Adolphe Merkle Institute - Chemin des Verdiers 4 - CH-1700 Fribourg - Phone +41 26 300 9254