Contribution of side‐chain chromophores to the optical activity of proteins: Model compound studies. IV. The indole chromophore of yohimbinic acid

The optical properties of the indole chromophore of the indole alkaloid yohimbinic acid have been investigated as a function of molecular conformation. Theoretical rotatory strengths have been calculated and compared with experimental circular dichroism spectra. Optical data that may be suitable for calculating the chiroptical properties of the near ultraviolet electronic transitions of the indole chromophores, which occur in tryptophan residues of proteins, have been developed. The far ultraviolet transitions of yohimbinic acid have also been investigated.