IFN-gamma-activated macrophages: detection by electron paramagnetic resonance of complexes between L-arginine-derived nitric oxide and non-heme iron proteins.
Interferon-gamma induces the L-Arginine-dependent pathway that leads to the formation of nitrogen oxides in murine macrophages with subsequent inhibition of mitochondrial non-heme iron-dependent enzymes. To evaluate a possible role of nitric oxide through binding to enzymes containing iron-prosthetic groups, we used Electron Paramagnetic Resonance spectroscopy. In IFN-gamma-activated macrophages, we observed the appearance of a signal in the g = 2.04 region which is consistent with that given by nitrosyl-iron-sulfur complexes. Appearance of this signal was dependent on the presence of L-Arginine in the culture medium. Furthermore, we detected a virtually identical signal in macrophages non stimulated by IFN-gamma, following exposure to nitric oxide (after addition of an excess of nitrite in the presence of ascorbate). These data suggest that L-Arginine-derived nitric oxide may alter the configuration of the catalytic site of certain mitochondrial enzymes by coordinating to iron at their iron-sulfur cluster(s).
Pellat
C
C
Unité 196 INSERM, Institut Curie, Paris, France.
Henry
Y
Y
Drapier
J C
JC
D000154:Aconitate Hydratase / Q000378:metabolism; D000818:Animals; D001120:Arginine / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D005260:Female; D007371:Interferon-gamma / Q000494:pharmacology*; D007501:Iron / Q000378:metabolism*; D007700:Kinetics; D008262:Macrophage Activation; D008264:Macrophages / Q000187:drug effects / Q000502:physiology*; D008667:Metalloproteins / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D009569:Nitric Oxide / Q000378:metabolism*; D011994:Recombinant Proteins
D008667:Metalloproteins; D011994:Recombinant Proteins; D009569:Nitric Oxide; D007371:Interferon-gamma; D001120:Arginine; D007501:Iron; D000154:Aconitate Hydratase