Decay of the transient Cu(B)-CO complex is accompanied by formation of the heme Fe-CO complex of cytochrome cbb(3)-CO at ambient temperature: evidence from time-resolved Fourier transform infrared spectroscopy.
Time-resolved step-scan Fourier infrared spectroscopy has been used to study the CO-bound cbb(3)-type cytochrome c oxidase from Pseudomonas stutzeri at room temperature. We observe a single band in the FTIR spectrum at 1956 cm(-1) (beta-form). The time-resolved data indicate that upon photolysis, CO is transferred from heme b(3) (nu(CO) = 1956 cm(-1)) to CuB (nu(CO) = 2064 cm(-1)). The decay of the 2065 cm(-1) peak (t(1/2) = 120 +/- 16 ms) and the development of the 1956 cm(-1) peak (t(1/2) = 144 +/- 8 ms ) suggest that formation of the Fe-CO complex is concurrent with the decay of the CuB-CO complex. The intensity ratio of the Fe-CO/CuB-CO (2.15) remains constant for all data points, and thus we conclude that no fraction of CO escapes the binuclear center at 293 K.
Stavrakis
Stavros
S
Department of Chemistry, University of Crete, 71409 Heraklion, Crete, Greece.
Koutsoupakis
Konstantinos
K
Pinakoulaki
Eftychia
E
Urbani
Andrea
A
Saraste
Matti
M
Varotsis
Constantinos
C
D002248:Carbon Monoxide / Q000737:chemistry* / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000378:metabolism; D006418:Heme / Q000737:chemistry* / Q000378:metabolism; D007501:Iron / Q000737:chemistry / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
D006418:Heme; D002248:Carbon Monoxide; D007501:Iron; C414443:cbb3 oxidase; D003576:Electron Transport Complex IV