Crystallographic and single-crystal spectral analysis of the peroxidase ferryl intermediate.
The ferryl [Fe(IV)O] intermediate is important in many heme enzymes, and thus, the precise nature of the Fe(IV)-O bond is critical in understanding enzymatic mechanisms. The 1.40 A crystal structure of cytochrome c peroxidase Compound I has been determined as a function of X-ray dose while the visible spectrum was being monitored. The Fe-O bond increases in length from 1.73 A in the low-X-ray dose structure to 1.90 A in the high-dose structure. The low-dose structure correlates well with an Fe(IV) horizontal lineO bond, while we postulate that the high-dose structure is the cryo-trapped Fe(III)-OH species previously thought to be an Fe(IV)-OH species.
Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697-3900, USA.
Yergalem T
YT
Meharenna
Tzanko
T
Doukov
Huiying
H
Li
S Michael
SM
Soltis
Thomas L
TL
Poulos
D018360:Crystallography, X-Ray; D003578:Cytochrome-c Peroxidase / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure
D005290:Ferric Compounds; C066317:ferryl iron; D007501:Iron; D003578:Cytochrome-c Peroxidase