The Speed of Allosteric Signaling Within a Single-Domain Protein

While much is known about different allosteric regulation mechanisms, the nature of signal and time scale on which it propagates remains elusive. The PDZ3 domain from postsynaptic density-95 protein a small with terminal third ?-helix, i.e., ?3-helix, to be allosterically active. By cross-linking helix an azobenzene moiety, we obtained photocontrollable variant. Photoswitching triggers its transition, resulting in change binding affinity peptide remote pocket. Using time-resolved infrared UV/vis spectroscopy, follow transduction reconstruct timeline through within 200 ns.