Time-resolved SSX: methodologies and applications to enzymes and light-sensitive proteins

This proposal is to carry out time-resolved serial synchrotron crystallography (TR-SSX) experiments on two biological photoreceptor proteins (OCP and CarH) and on esterase enzymes. To trigger the reaction in the microcrystalline proteins, laser-illumination will be used for the former, and rapid mixing for the latter. The proposal follows up on experiments carried out during our previous ID29 BAG (2022 – 2024) beamtimes, during which static SSX data sets were collected on most of our target proteins mentioned in the application. Since the required nanosecond laser was not available, most of the experiments proposed previously remain to be carried out. We have collected high-resolution TR-SFX data on the ps – ms time scale for OCP and CarH that will be either complemented or compared to TR-SSX data to be collected on ID29.