A mufti-national team, led by University of Wisconsin – Milwaukee (UWM) physics Professor Marius Schmidt, have successfully used X-ray pulses emitted by a free-electron laser source (the XFEL at the SLAC National Accelerator Laboratory) to track changes in a crystallized protein as it reacts to light. For the first time, the structure of a photo-active yellow protein (PYP) was observed as it changed its shape from an initial ‘trans’ configuration to a new ‘cis’ configuration after exposure to light. The team participating in the research includes UWM Distinguished Professor Abbas Ourmazd, Associate Professor Peter Schwander, former UWM postdoctoral researcher Dr. Kanupriya Pande, and three current postdoctoral researchers and graduate students. Other team members include personnel from ten national and international institutions. A research report Femtosecond structural dynamics drives the trans/cis isomerization in photoactive yellow protein was recently published in Science magazine. In the near future the team will attempt to obtain femtosecond details over a longer time period. This could ultimately allow scientists to modify protein function by exposing the protein to light. More information can be found at Split-second imaging sheds light on biology’s grand questions.