The Influence of the Aromatic Amino Acid Side-Chains on the Sign of the Soret Cotton Effect in Chironomus Hemoglobin (CTT III)

Abstract

The origin of the positive Soret Cotton effect of myoglobin was calculated by Hsu and WOODY on the basis of a mechanism taking into account the coupling of the Soret and aromatic side-chain π—π* transitions. HUBER and coworkers have worked out the atomic coordinates of a monomeric insect hemoglobin which exhibits a negative Soret Cotton effect. It seemed of some importance to examine the capability of this mechanism to explain the observed inversion of sign. The calculations resulted indeed in a negative total rotational strength (—0,2 DBM), the main contributions arising from phenylalanine residues.