A Note on Circular‐Dichroic‐Constrained Prediction of Protein Secondary Structure

Circular dichroic (CD) spectra of bovine immunosuppressant binding proteins FKBP12 and FKBP25, and cyclophilins (peptidylprolyl isomerases) A (bCyP‐18) and B (bCyP‐20), the immunophilins which selectively bind the clinically useful immunosuppressants FK506, rapamycin and cyclosporin A, respectively, were analysed using the singular‐value‐decomposition algorithm augmented by a simplified variable selection method. The differences between the CD‐estimated values of α‐helix, β‐structure and β‐turn and those predicted by the Chou‐Fasman algorithm were minimized using the CD data as constraints of an algorithm which utilizes the method of hierarchical updating of quasi‐equipotential peptide segments of the Chou‐Fasman prediction. The method allows one to correct the Chou‐Fasman prediction of secondary structures in globular proteins.