Characterization of iron dinitrosyl species formed in the reaction of nitric oxide with a biological Rieske center.
Reactions of nitric oxide with cysteine-ligated iron-sulfur cluster proteins typically result in disassembly of the iron-sulfur core and formation of dinitrosyl iron complexes (DNICs). Here we report the first evidence that DNICs also form in the reaction of NO with Rieske-type [2Fe-2S] clusters. Upon treatment of a Rieske protein, component C of toluene/o-xylene monooxygenase from Pseudomonas sp. OX1, with an excess of NO(g) or NO-generators S-nitroso-N-acetyl-D,L-pencillamine and diethylamine NONOate, the absorbance bands of the [2Fe-2S] cluster are extinguished and replaced by a new feature that slowly grows in at 367 nm. Analysis of the reaction products by electron paramagnetic resonance, Mössbauer, and nuclear resonance vibrational spectroscopy reveals that the primary product of the reaction is a thiolate-bridged diiron tetranitrosyl species, [Fe(2)(μ-SCys)(2)(NO)(4)], having a Roussin's red ester (RRE) formula, and that mononuclear DNICs account for only a minor fraction of nitrosylated iron. Reduction of this RRE reaction product with sodium dithionite produces the one-electron-reduced RRE, having absorptions at 640 and 960 nm. These results demonstrate that NO reacts readily with a Rieske center in a protein and suggest that dinuclear RRE species, not mononuclear DNICs, may be the primary iron dinitrosyl species responsible for the pathological and physiological effects of nitric oxide in such systems in biology.
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Christine E
CE
Tinberg
Zachary J
ZJ
Tonzetich
Hongxin
H
Wang
Loi H
LH
Do
Yoshitaka
Y
Yoda
Stephen P
SP
Cramer
Stephen J
SJ
Lippard
D040761:Biomimetic Materials / Q000737:chemistry; D014450:Electron Transport Complex III / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D020030:Nitric Oxide Donors / Q000737:chemistry; D009589:Nitrogen Oxides / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000737:chemistry*; D011487:Protein Conformation; D011549:Pseudomonas / Q000201:enzymology
D020030:Nitric Oxide Donors; D009589:Nitrogen Oxides; C037989:Rieske iron-sulfur protein; D009569:Nitric Oxide; C073661:dinitrosyl iron complex; D007501:Iron; D010105:Oxygenases; C067624:xylene monooxygenase; D014450:Electron Transport Complex III