Heme/heme redox interaction and resolution of individual optical absorption spectra of the hemes in cytochrome bd from Escherichia coli
| Autor: | Dmitry A. Bloch, Tatsushi Mogi, Michael I. Verkhovsky, Vitaliy B. Borisov |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Cytochrome
Stereochemistry Potentiometric titration Biophysics Respiratory chain α-band Heme Photochemistry Biochemistry Redox Absorption 03 medical and health sciences chemistry.chemical_compound Redox titration Chlorin Electrochemistry Escherichia coli Spectral decomposition Anaerobiosis Spectroelectrochemistry 030304 developmental biology 0303 health sciences biology Escherichia coli Proteins Spectrum Analysis 030302 biochemistry & molecular biology Cytochrome d Titrimetry Cell Biology Hydrogen-Ion Concentration Soret band Cytochrome b Group OTTLE Electron Transport Chain Complex Proteins chemistry biology.protein Molecular bioenergetics Cytochromes Bacterial metabolism Titration Oxidoreductases Oxidation-Reduction β-band |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1787:1246-1253 |
| ISSN: | 0005-2728 |
| DOI: | 10.1016/j.bbabio.2009.05.003 |
| Popis: | Cytochrome bd is a terminal component of the respiratory chain of Escherichia coli catalyzing reduction of molecular oxygen to water. It contains three hemes, b(558), b(595), and d. The detailed spectroelectrochemical redox titration and numerical modeling of the data reveal significant redox interaction between the low-spin heme b(558) and high-spin heme b(595), whereas the interaction between heme d and either hemes b appears to be rather weak. However, the presence of heme d itself decreases much larger interaction between the two hemes b. Fitting the titration data with a model where redox interaction between the hemes is explicitly included makes it possible to extract individual absorption spectra of all hemes. The alpha- and beta-band reduced-minus-oxidized difference spectra agree with the data published earlier ([22] J.G. Koland, M.J. Miller, R.B. Gennis, Potentiometric analysis of the purified cytochrome d terminal oxidase complex from Escherichia coli, Biochemistry 23 (1984) 1051-1056., and [23] R.M. Lorence, J.G. Koland, R.B. Gennis, Coulometric and spectroscopic analysis of the purified cytochrome d complex of Escherichia coli: evidence for the identification of "cytochrome a(1)" as cytochrome b(595), Biochemistry 25 (1986) 2314-2321.). The Soret band spectra show lambda(max)=429.5 nm, lambda(min) approximately 413 nm (heme b(558)), lambda(max)=439 nm, lambda(min) approximately 400+/-1 nm (heme b(595)), and lambda(max)=430 nm, lambda(min)=405 nm (heme d). The spectral contribution of heme d to the complex Soret band is much smaller than those of either hemes b; the Soret/alpha (DeltaA(430):DeltaA(629)) ratio for heme d is 1.6. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect