Circular dichroism spectroscopy is a form of light absorption phenomenon that measures the difference in absorbance of right- and left-circularly polarized light. Preferential absorption of either right or left circularly polarized light by the sample leads to detection of elliptical light. Spectral signature of ellipticity as a function of various wavelengths of light gives structural information of biomolecules. CD spectroscopy can be used to monitor: (1) secondary structure, (2) conformational changes, (3) environmental effects, (4) protein folding and denaturation, and (5) dynamics. Information from CD spectroscopy is complimentary to structural information obtained by other methods, such as NMR and x-ray crystallography.

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