Structure and quantum chemical characterization of chloroperoxidase compound 0, a common reaction intermediate of diverse heme enzymes.
We have determined the crystal structure of the chloroperoxidase (CPO) hydroperoxo reaction intermediate (CPO compound 0) at 1.75-A resolution. The intermediate was generated through controlled photoreduction of the CPO oxygen complex during x-ray data collection, which was monitored by recording of the crystal absorption spectra. Initially, the peroxo-anion species was formed and then protonated to yield compound 0. Quantum chemical calculations indicate that the peroxo-anion species is not stable and collapses instantaneously to compound 0. Compound 0 is present in the ferric low-spin doublet ground state and is characterized by a long O O bond length of 1.5 A and a Fe O bond distance of 1.8 A, which is also observed in the crystal structure.
Kühnel
Karin
K
Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany.
Derat
Etienne
E
Terner
James
J
Shaik
Sason
S
Schlichting
Ilme
I
D001665:Binding Sites; D002711:Chloride Peroxidase / Q000378:metabolism*; D003460:Crystallization; D005290:Ferric Compounds / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*
D005290:Ferric Compounds; D006861:Hydrogen Peroxide; D002711:Chloride Peroxidase