Recent time-resolved studies have revealed the switching behavior of single photosynthetic light-harvesting complexes. In this work, we suggest a diffusion-controlled model describing essential protein dynamics underlying this switching. The calculated blinking statistics are compared with the experimental result and not only reproduce the power-law behavior at intermediate times, but also follow the experimentally observed deviations from such behavior on a shorter time scale. We propose that the coupling of fast protein dynamics to a specific slow coordinate is at the basis of regulatory switching. © 2012 American Chemical Society.