Direct observation of protein refolding in mixed surfactant systems using contrast variation SANS

Protein renaturation in the presence of ionic-nonionic surfactant mixtures was recently reported for a handful of systems using spectroscopy and small-angle X-ray scattering. However, a mechanistic understanding of this phenomenon is still lacking, and the driving forces and conformational landscape of the protein are yet to be defined. In this experiment, we will use contrast-variation small-angle neutron scattering to elaborate a detailed model of interaction between human growth hormone, sodium dodecyl sulfate and dodecyl maltoside. The use of specific deuteration schemes will provide contrasts that discriminate the contribution to the scattering from different parts of the system, allowing to focus on structural changes on the protein and migration of surfactants between protein and micelles. This investigation is part of an industrial collaboration with Ferring Pharmaceuticals A/S.