An Fe2IVO2 diamond core structure for the key intermediate Q of methane monooxygenase.
A new paradigm for oxygen activation is required for enzymes such as methane monooxygenase (MMO), for which catalysis depends on a nonheme diiron center instead of the more familiar Fe-porphyrin cofactor. On the basis of precedents from synthetic diiron complexes, a high-valent Fe2(micro-O)2 diamond core has been proposed as the key oxidizing species for MMO and other nonheme diiron enzymes such as ribonucleotide reductase and fatty acid desaturase. The presence of a single short Fe-O bond (1.77 angstroms) per Fe atom and an Fe-Fe distance of 2.46 angstroms in MMO reaction intermediate Q, obtained from extended x-ray absorption fine structure and Mössbauer analysis, provides spectroscopic evidence that the diiron center in Q has an Fe2IVO2 diamond core.
Shu
L
L
Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455, USA.
Nesheim
J C
JC
Kauffmann
K
K
Münck
E
E
Lipscomb
J D
JD
Que
L
L
D001665:Binding Sites; D002384:Catalysis; D018360:Crystallography, X-Ray; D019281:Dimerization; D006088:Gram-Negative Aerobic Bacteria / Q000201:enzymology*; D007501:Iron / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010105:Oxygenases / Q000737:chemistry* / Q000378:metabolism; D015204:Spectroscopy, Mossbauer; D013057:Spectrum Analysis
C066317:ferryl iron; D007501:Iron; D010105:Oxygenases; C021555:methane monooxygenase; D010100:Oxygen