What triggers conformational change in proteins during the assembly of beta-sheet materials?

Some of the most fascinating materials in nature, such as spider silk, are built from proteins.

The key to the extraordinary properties of silk is the hierarchical organization of the protein molecules with a substantial amount of beta-sheet structure providing the strength.

The transition from the alpha-helical precursor protein to the beta-sheet rich fiber is tightly controlled in the spiders but happens extremely fast when triggered. The details of this triggering machinery are only vaguely understood.

In the proposed project we will explore the fundamental mechanisms of this process by studying the structural transitions in spider silk-derived proteins and peptides.

Comparison with protein segments from soy proteins, which can undergo similar structural transitions, will reveal whether there are specific properties that are unique for the silk proteins.

The planned experiments will address the thermodynamic and kinetic principles of the structural transitions in bulk solutions as function of pH and ion concentrations.

We will then use the surface-specific method vibrational sum frequency generation spectroscopy to monitor the structural transition at air-water and solid-water interfaces.

Finally, we will attempt to follow the structural propagation within the studied proteins to elucidate the relevant chain of events.

The knowledge will be used in the development of new biobased materials for the transformation to a sustainable society.