VCD of Biological Substances: Effects of d-Amino Acid Residues on Supramolecular Chirality

This chapter describes the VCD of biological substances. Targets are amino acids, oligopeptides, proteins and protein aggregates. Solid-state VCD (denoted as SD-VCD) is developed to study these compounds in solid states. Notably the enhancement of signal intensity is observed for crystalline amino acids and oligopeptides. VCD data thus accumulated provide a database to characterize a wide scope of these molecules. For solution samples, the advantage of VCD is demonstrated in the case of biologically active oligopeptides containing d-amino acid residues. For these compounds, the conformational changes induced in a peptide chain are discussed when one l-residue is replaced with the corresponding d-residue.