Circular dichroism techniques for the identification of intrinsically disordered proteins (IDPs)

CHEMES, L.B.; ALONSO, L.G.; NOVAL, G.; DE PRAT-GAY, G.

Intrinsically Disordered Proteins: Volume I. Experimental Techniques

Humana Press-Springer Protocols

Lugar: New Jersey; Año: 2010;

SUMMARY Circular dichroism (CD) spectroscopy is a simple and powerful technique, which allows for the assessment of the conformational properties of a protein or protein domain. Intrinsically disordered proteins (IDPs) differ from random coil polypeptides in that different regions present specific conformational preferences, exhibiting dynamic residual secondary structure content (1). These dynamic secondary structure elements can be stabilized by different chemical (solvent, ionic strength, pH) or physical (temperature) agents. In the present chapter, we present the basic methodology for performing Far-UV CD measurements and identifying intrinsically disordered regions on a protein of interest, and several protocols for the detection of residual secondary structure present in the protein under study. These techniques are straightforward to perform, and can be tackled previously to the use of more complex methodologies such as NMR measurements. Keywords: Circular dichorism, Intrinsically disordered protein, secondary structure, CD spectrum, polyrpoline type II (PII) conformation, alpha helix conformation.