Publisher Summary Circular dichroism (CD) is a spectroscopic method which depends on the fact that certain molecules interact differently with right and left circularly polarized light. Circularly polarized light is chiral—that is, it occurs in two nonsuperimposable forms that are mirror images of one another. To discriminate between the two chiral forms of light, a molecule must be chiral, including the vast majority of biological molecules. A method that can discern the subtle differences between non superimposable mirror image molecules (enantiomers) must be highly sensitive to the three-dimensional features of molecules—that is, to conformation. Binding of ligands or protein-protein and protein–DNA interactions can also alter the circular dichroism spectrum of the protein and/or nucleic acid. These changes in CD can be used to determine equilibrium constants, and they can also provide evidence for conformational changes. Thus, CD can provide information about the secondary structure of proteins and nucleic acids and about the binding of ligands to these types of macromolecule.

[4] Circular dichroism

Ferricytochrome c: I. GENERAL FEATURES OF THE HORSE AND BONITO PROTEINS AT 2.8 A RESOLUTION

Spin—spin coupling and the conformational states of peptide systems

(1974). Aromatic Contributions To Circular Dichroism Spectra Of Protein. CRC Critical Reviews in Biochemistry: Vol. 2, No. 1, pp. 113-175.

Aromatic contributions to circular dichroism spectra of proteins.

Publisher Summary This chapter discusses the methodology of circular dichroism (CD) and optical rotatory dispersion (ORD) data gathering and analysis in the rapidly changing field of protein structure, making use of synthetic polypeptide studies when necessary. ORD is the measurement, as a function of wavelength, of a molecule's ability to rotate the plane of linearly polarized light. CD is similar data evaluating the molecule's unequal absorption of right- and left-handed circularly polarized light. CD and ORD can yield useful estimates of protein secondary structure. Although all the amino acids except glycine contain at least one asymmetric carbon atom, most amino acids display only small ORD and CD bands. It is the conformation of the protein—that is, the asymmetric and periodic arrangement of peptide units in space, which gives rise to their characteristic ORD and CD spectra. In recent years, X-ray diffraction analysis has lead to the complete mapping of the peptide backbone and side-chain positions of lysozyme, several other enzymes, and quite a few other proteins in the solid state.

Circular dichroism and optical rotatory dispersion of proteins and polypeptides.

Temperature dependence of amide proton chemical shifts: the secondary structures of gramicidin S and valinomycin.

https://www.jbc.org/content/242/19/4441.full.pdf

The Heme Chromophore in the Ultraviolet

Correlation of light scattering and absorption flattening effects with distortions in the circular dichroism patterns of mitochondrial membrane fragments

Dan W. Urry

Papers

Temperature dependence of amide proton chemical shifts: the secondary structures of gramicidin S and valinomycin.

The Heme Chromophore in the Ultraviolet

Correlation of light scattering and absorption flattening effects with distortions in the circular dichroism patterns of mitochondrial membrane fragments

Reciprocal Relations and Proximity of Bases in Pyridine Dinucleotides

Circular dichroism and optical rotatory dispersion of gramicidin S in aqueous solution.