On the estimation of the secondary structures of proteins from circular dichroism spectra

Abstract

1. 1. The three-component fitting of protein circular dichroism (CD) spectra with basis spectra for helical, β-sheet and unordered structure calculated from the CD spectra of reference proteins of known structural composition is considered. 2. 2. The reference and analyzed protein spectra should be shown to have the same basis. This can be checked by matrix rank analysis which is proposed prior to curve fitting analysis of protein CD spectra. 3. 3. The procedure is illustrated for human erythrocuprein. 4. 4. It is shown that CD spectra of this protein have the same three-component basis, within the limits of experimental error, as CD spectra of myoglobin, lysozyme, ribonuclease, lactate dehydrogenase and papain, and basis spectra derived from the spectra of the reference proteins are used to fit the erythrocuprein spectra.