OPTICAL ROTATORY PROPERTIES OF HEMERYTHRIN IN ULTRAVIOLET RANGE

Circular dichroic spectra have been recorded in the range from 200 to about 350 nm for methemerythrin, with its iron coordinated with different ligands. Major contributions to dichroic absorption in the 290-nm region can be ascribed to tyrosine residues, and there are also some contributions from the iron atoms. In the peptide n-π* and π-π* region, methemerythrin shows circular dichroic spectra similar to α-helical polypeptides. These spectra, and hence the presumed helix content (75%), do not change with changes in ligand bound to iron or upon dissociation of the protein into monomers. © 1969.