Applying broadband terahertz time-domain spectroscopy to the analysis of crystalline proteins: a dehydration study

The application of terahertz time-domain spectroscopy and imaging to the study of proteins in crystalline form is demonstrated. Terahertz time-domain spectroscopy is particularly sensitive to the long-range ordering of molecules, with proven utility for the spectroscopy of crystalline biological small molecules. Here, the terahertz time-domain absorption response of a macromolecular protein single crystal is investigated for the first time. In particular, the effect of dehydration on the terahertz absorption coefficient of tetragonal hen egg white lysozyme crystals is reported.