Structural characterization by EXAFS spectroscopy of the binuclear iron center in protein A of methane monooxygenase from methylococcus capsulatus (bath)
Soluble methane monooxygenase (MMO) from Methylococcus capsulatus (Bath) activates dioxygen for incorporation into a remarkable variety of substrates including methane, which is required for bacterial growth (eq 1). MMO is a three component CH/sub 4/ + NADH + H/sup +/ + O/sub 2/ /sup MMO/ ..-->.. CH/sub 3/OH + NAD/sup +/ + H/sub 2/O (1) enzyme. Protein A (M/sub r/ 210,000), believed to be the oxygenase component, contains two iron atoms. Protein B (M/sub r/ 15,700) serves a regulatory function and lacks prosthetic groups, while protein C, the reductase component of the enzyme, is an iron-sulfur flavoprotein (M/sub r/ 42,000) responsible for electron transfer from NADH to protein A. Recently, a binuclear iron center was postulated to occur in protein A based on the finding that one-electron reduction gives rise to electron spin resonance (ESR) signals (g 1.95, 1.88, 1.78) very similar to those observed for the binuclear mixed-valence Fe/sub 2/(III,II) centers in semimet hemerythrin (Hr) and purple acid phosphatase (PAP). In conjunction with model studies, extended X-ray absorption fine structure (EXAFS) spectroscopy has proven to be a powerful method for identifying bridged binuclear iron centers in Hr, ribonucleotide reductase (RR), and PAP. Here the authors report iron K-edge EXAFS results on semireduced protein A of MMO which support the occurrence of a binuclear iron center (Fe-Fe distance, 3.41 A), with no short ..mu..-oxo bridge.
- Research Organization:
- Stanford Univ., CA (USA)
- OSTI ID:
- 6975229
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 110:7; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
Similar Records
X-ray absorption spectroscopic studies of the dinuclear iron center in methane monooxygenase and the sulfure and chlorine centers in photographic materials
X-Ray Absorption Spectroscopic Studies of the Dinuclear Iron Center in Methane Monooxygenase and the Sulfure and Chlorine Centers in Photographic Materials
Related Subjects
400201* -- Chemical & Physicochemical Properties
DATA
ENZYMES
EXPERIMENTAL DATA
FINE STRUCTURE
FOURIER TRANSFORM SPECTROMETERS
INFORMATION
MEASURING INSTRUMENTS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDOREDUCTASES
OXYGENASES
PROTEINS
SPECTROMETERS
STRUCTURAL CHEMICAL ANALYSIS