Synchrotron radiation circular dichroism (SRCD) spectroscopy is an emerging technique in structural biology with particular value for accurate secondary structure determination, monitoring protein folding and kinetics, and drug discovery. This paper discusses new biomedical applications of SRCD, notably the identification of conformational changes associated with a mutant protein that causes disease, and the development of methods for identification of fold motifs in the context of structural genomics programmes. In addition, it presents for the first time, very low wavelength (below 154 nm) data for a protein in aqueous solution, demonstrating the presence of heretofore-unseen electronic transitions.