Vibrational spectroscopy has long been used to study protein structure and dynamics. However the data is usually spectrally congested, and information about sites of interest is not easily accessible. With the help of in vitro production methods to isotope label certain amino acids, or site-specifically isotope label it is possible to identify and study sites of interest. However this has had limitations in which amino acids can be utilized, or with very low yields. Recently we published an efficient method for site-specific labeling of any amino acid in the protein. In addition, we have been studying the structural dynamics of bacterial phytochromes with vibrational spectroscopy where we also have utilized in vitro production methods and isotope labeling.