It has been shown in the last decade that ultraviolet (UV) resonance Raman (RR) spectroscopy is a powerful tool for studying protein structures and their dynamics. Changes in intensities and frequencies of UV Raman bands arising from aromatic side chains of proteins have been correlated with their structural or environmental changes, particularly for tyrosine (Tyr) and tryptophan (Trp) residues, in the same way as that for visible excitations. However, in comparison with visible excitation, UV excitation contains a high possibility of causing photochemical degradation of samples; accordingly, special illumination systems of samples, such as a wire-guided flow system, have been devised for individual experiments. Flow cell systems generally require a large volume of samples, and therefore it has been difficult to apply the UVRR technique to uncommon samples like mutant proteins for which a large number of samples are not available. The other technical problem is difficulty in measuring the spectra of solid samples since powder or crystalline samples are easily degraded by irradiation of the UV laser because of their strong UV absorption. The higher background in these measurements also brings about large noise in the spectra.
Shoji Kaminaka and Teizo Kitagawa, "Novel Spinning Cell System for UVRR Measurements of Powder and Small-Volume Solution Samples in Back-Scattering Geometry: Application to Solid Tryptophan and Mutant Hemoglobin Solution," Appl. Spectrosc. 49, 685-687 (1995)