J. Phys. Colloques
Volume 47, Number C8, Décembre 1986EXAFS and Near Edge Structure IV
|Page(s)||C8-1151 - C8-1154|
J. Phys. Colloques 47 (1986) C8-1151-C8-1154
EXAFS STUDY OF ACTIVE INTERMEDIATES : HEME ENZYMES AND MODEL COMPOUNDSLUNG-SHAN KAU1, E.W. SVASTITS2, M. SONO2, J.H. DAWSON2 et K.O. HODGSON1
1 Department of Chemistry, Stanford University, Stanford, CA 94305, U.S.A.
2 Department of Chemistry, University of South Carolina, Columbia, SC 29208, U.S.A.
The iron coordination structures of the oxygenated cytochrome P-450-CAM and chloroperoxidase and of a number of penta- and hexa-coordinate ferrous porphyrin complexes containing biologically relevant, sulfur axial ligands have been investigatied by EXAFS spectroscopy. The two oxygenated enzymes have both been found to contain a sulfur atom located 2.37 Å from the central heme iron. In the CO-ligated series of model complexes, two distinct categories of Fe-Sax distances have been observed that correlate with thiolate and non-thiolate ligation (~2.33 and ~2.41 Å, respectively) . The data for these model ferrous-CO ccomplexes, together with previously reported Fe-S distance in oxygenated heme iron model complexes ; allows the sulfur atoms in oxygenated P-450-CAM and chloroperoxidase to be identified as a thiolate sulfur.