EXAFS Studies on the c-Heme Environment in Native and Chemically Modified Cytochromes

Abstract

The chemical environment of the c heme in low-molecular weight and water soluble cytochromes like cytochrome c is well known thanks to the X-ray diffraction studies carried out by Dickerson and coworkers (Ref.1) for both the oxidation states of the molecule and for a number of different species. Their conclusions, summarized in Table 1 as far as the interatomic distances of the first five shells surrounding the chromophores are concerned, have been confirmed and substantiated by various physical and biochemical methods, including XAS (see, for example, Ref. 2).