The use of circular dichroism spectroscopy to study protein folding, form and function

Circular Dichroism (CD) is a spectroscopic technique widely used for the evaluation of the conformation and stability of proteins in several environmental conditions like temperature, ionic strength, and presence of solutes or small molecules. Circular Dichroism spectroscopy is non-destructive, relatively easy to operate, requires small amount of sample and few data collection. Additionally, data analyses are fast. Chiefly because of the advantages associated with the technique, CD is present in almost all laboratories involved with protein analysis even though it mainly provides low resolution information when compared with other techniques. However, this technique is sometimes not well appreciated due to some over or misinterpretation while relating Circular Dichroism with structure. Here we present important principles and other valuable tips to help experimentalists with the analysis and interpretation of CD data. Key words: Circular dichroism, protein folding, protein stability, spectroscopy.