Superoxo, mu-peroxo, and mu-oxo complexes from heme/O2 and heme-Cu/O2 reactivity: copper ligand influences in cytochrome c oxidase models.
The O(2)-reaction chemistry of 1:1 mixtures of (F(8))Fe(II) (1; F(8) = tetrakis(2,6-diflurorophenyl)porphyrinate) and [(L(Me(2))N)Cu(I)](+) (2; L(Me(2))N = N,N-bis(2-[2-(N',N'-4-dimethylamino)pyridyl]ethyl)methylamine) is described, to model aspects of the chemistry occurring in cytochrome c oxidase. Spectroscopic investigations, along with stopped-flow kinetics, reveal that low-temperature oxygenation of 1/2 leads to rapid formation of a heme-superoxo species (F(8))Fe(III)-(O(2)(-)) (3), whether or not 2 is present. Complex 3 subsequently reacts with 2 to form [(F(8))Fe(III)-(O(2)(2-))-Cu(II)(L(Me(2))N)](+) (4), which thermally converts to [(F(8))Fe(III)-(O)-Cu(II)(L(Me(2))N)](+) (5), which has an unusually bent (Fe-O-Cu) bond moiety. Tridentate chelation, compared with tetradentate, is shown to dramatically lower the nu(O-O) values observed in 4 and give rise to the novel structural features in 5.
Kim
Eunsuk
E
Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA.
Helton
Matthew E
ME
Wasser
Ian M
IM
Karlin
Kenneth D
KD
Lu
Shen
S
Huang
Hong-Wei
HW
Moenne-Loccoz
Pierre
P
Incarvito
Christopher D
CD
Rheingold
Arnold L
AL
Honecker
Marcus
M
Kaderli
Susan
S
Zuberbuhler
Andreas D
AD
D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000378:metabolism*; D006418:Heme / Q000378:metabolism*; D008958:Models, Molecular; D010100:Oxygen / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation
D006418:Heme; D003576:Electron Transport Complex IV; D010100:Oxygen