Circular dichroism (CD) spectroscopy measures differences in the absorption of left-handed versus right-handed polarized light that arise due to structural asymmetry. CD spectroscopy has become a very useful technique for characterization of biomolecules. Characterization information obtained from CD include:
Determination of secondary structure content for macromolecules (% -helix, -sheet);
Solution effects (salts, pH, organics) on the conformation of macromolecules;
Kinetic information on protein folding, unfolding, denaturation or aggregation;
Thermodynamic characterization of macromolecules and the effects of solution conditions and chemical denaturants on the stability and reversibility of unfolding;
Tertiary structure changes around aromatic residues;
Determination of protein-protein interactions and their effects on protein conformation;
Demonstrating conformational equivalence of material from different manufacturing processes.
The PiStar-180 spectrometer (Applied Photophysics) available at the SSSC is designed for both steady-state and kinetic CD applications. In addition to CD detection, the PiStar-180 spectrometer can also do measurements in absorbance or fluorescence modes.