Low-frequency dynamics of functional proteins studied by terahertz time-domain spectroscopy

We applied terahertz time-domain spectroscopy on myosin II subfragment 1 (S1) to monitor temperature and hydration dependence of its low-frequency dynamics. In the absorption spectra of both apo and holo S1 (ATP-free and bound form, respectively), so-called dynamical transition was observed at around 190 K only when they are hydrated.