THz differential spectroscopy of Rhodopsin

In this work we record THz spectra of Bovine Rhodopsin Rod Outer Segment (ROS) suspended in buffer. THz difference spectra (calculated using spectra collected before and after light excitation) were used to identify signals arising from the domain structural transformations which occur during the light-activation process. The Molecular Modelling Toolkit (MMTK) software package was used to calculate the theoretical normal mode density for both dark-state and light-activated rhodopsin. The simulation results were used to guide the interpretation of spectra observed.