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), Vol. 110:7
- 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
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
OXYGENASES
STRUCTURAL CHEMICAL ANALYSIS
PROTEINS
EXPERIMENTAL DATA
FINE STRUCTURE
FOURIER TRANSFORM SPECTROMETERS
DATA
ENZYMES
INFORMATION
MEASURING INSTRUMENTS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDOREDUCTASES
SPECTROMETERS
400201* - Chemical & Physicochemical Properties