The study demonstrates that there are more factors at work than just mutual repulsion
Deploying various solvent additives, such as biomacromolecules, sugars and salts, the RUB researchers have imitated various cellular conditions and analysed the way they affect the model protein ubiquitin. They demonstrated that the proteins' behaviour is affected by more than just mutual repulsion between protein and solvent additive. In thermodynamic studies, different stabilisation and destabilisation mechanisms were discovered. Contrary to the expected so-called entropic stabilisation based on the excluded volume effect the researchers observed a so-called enthalpic stabilisation of ubiquitin in the presence of macromolecules, sugars and salts. Enthalpic stabilisation is directly correlated to the strengthening of the chemical bonds in the biologically active status and cannot be explained away with the protein's more compact shape being purely volume-based.
Water as mediator between protein and dissolved substances
The researchers attribute the enthalpic stabilisation phenomenon to a water-mediated process: protein and solvent additive do not interact directly, but following a modification of the water properties of the solvent additives' hydration water, the hydrogen bridge bonds in the protein's biologically active status are optimised. The project was financed by the Returnee Programme o
|Contact: Dr. Simon Ebbinghaus|