Microsecond time-resolved X-ray scattering by utilizing MHz repetition rate at second-generation XFELs

Here, we show how MHz repetition rates at X-ray free electron lasers (XFELs) can be used to produce microsecond time-series of protein scattering with exceptionally low noise levels of 0.001%. We demonstrate the approach by deriving new mechanistic insight into Jɑ helix unfolding of a Light-Oxygen-Voltage (LOV) photosensory domain. This time-resolved acquisition strategy is easy to implement and widely applicable for direct observation of structural dynamics of many biochemical processes.