X-ray absorption spectroscopic characterization of a cytochrome P450 compound II derivative

Martin Newcomb, James A. Halgrimson, John H. Horner, Erik C. Wasinger, Lin X. Chen, Stephen G. Sligar

Research output: Contribution to journalArticlepeer-review


The cytochrome P450 enzyme CYP119, its compound II derivative, and its nitrosyl complex were studied by iron K-edge x-ray absorption spectroscopy. The compound II derivative was prepared by reaction of the resting enzyme with peroxynitrite and had a lifetime of ≈10 s at 23°C. The CYP119 nitrosyl complex was prepared by reaction of the enzyme with nitrogen monoxide gas or with a nitrosyl donor and was stable at 23°C for hours. Samples of CYP119 and its derivatives were studied by x-ray absorption spectroscopy at temperatures below 140 (K) at the Advanced Photon Source of Argonne National Laboratory. The x-ray absorption near-edge structure spectra displayed shifts in edge and pre-edge energies consistent with increasing effective positive charge on iron in the series native CYP119 < CYP119 nitrosyl complex < CYP119 compound II derivative. Extended x-ray absorption fine structure spectra were simulated with good fits for k = 12 Å-1 for native CYP119 and k = 13 Å-1 for both the nitrosyl complex and the compound II derivative. The important structural features for the compound II derivative were an iron-oxygen bond length of 1.82 Å and an iron-sulfur bond length of 2.24 Å, both of which indicate an iron-oxygen single bond in a ferryl-hydroxide, FeIVOH, moiety.

Original languageEnglish (US)
Pages (from-to)8179-8184
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number24
StatePublished - Jun 17 2008


  • Ferryl-oxo

ASJC Scopus subject areas

  • General


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