Single particle protein structural dynamics using XFEL radiation

We will develop a new experimental approach that allows the dynamical response of single biomolecules to be characterized in real-time using XFEL radiation.

We will focus our studies on ligand gated ion channels (LGIC), which are integral membrane proteins that open or close in response to the binding of ligands, thereby enabling electrochemical signals to propagate between neurons.

Our key idea is to attach two elongated gold nanoparticles (nanorods) onto a single LGIC, but on opposite sides of its transmembrane domain.

The relative orientation of two nanorods will be retrieved in coherent x-ray imaging (CXI) studies at EuXFEL one protein:nanoparticle complex at a time.

By recording tens of thousands of CXI measurements from LGIC:nanoparticle complexes as a function of the time-delay after mixing with a ligand, we will visualize protein twisting motions as LGICs open or close in real time.

Time-resolved X-ray scattering studies of solubilized LGICs in their equilibrium state will complement our single-molecule studies using XFEL radiation.

These methodology developments within the Röntgen-Ångrström cluster framework have the potential to become broadly used, versatile tools for understanding biomolecular structural dynamics.