Circular dichroism (CD) spectroscopy observes differences in the absorption of left and right circularly polarized light by chiral molecules. CD spectroscopy is divided into far and near UV applications.
There are many applications for CD spectroscopy in Chemistry, Biochemistry, Biology, Physics, Chemical and Biological Engineering, and Material Sciences. In Biology and Biophysics, far UV CD spectroscopy (180 to 240 nm) makes use of the optical activity of the protein backbone and can be used to investigate the secondary structure of proteins. In contrast, near UV CD spectroscopy (250 to 350 nm) can produce a finger print of the environment of aromatic amino acids in proteins. But CD spectroscopy does not stop here. It is also an invaluable tool to investigate peptides, lipids, RNA and DNA.
Exciting Possibilities in Biology, Biochemistry and Biophysics:
Secondary structure of proteins, peptides, RNA and DNA
Folding and refolding
Ligand induced changes in structure and stability
Tertiary structure and conformational changes of proteins (near UV CD observing contributions from phenylalanines, tyrosines and tryptophans)
Stopped-flow spectroscopy in single mixing or sequential mixing experiments using CD, absorption, fluorescence or fluorescence polarization