Abstract
Femtosecond spectroscopy was performed on CO-liganded (fully reduced and mixed-valence states) and O2-liganded quinol oxidase bd from Escherichia coli. Substantial polarization effects, unprecedented for optical studies of heme proteins, were observed in the CO photodissociation spectra, implying interactions between heme d (the chlorin ligand binding site) and the close-lying heme b595 on the picosecond time scale; this general result is fully consistent with previous work [Vos, M. H., Borisov, V. B., Liebl, U., Martin, J.-L., and Konstantinov, A. A. (2000) Proc. Natl. Acad. Sci. U.S.A. 97, 1554-1559]. Analysis of the data obtained under isotropic and anisotropic polarization conditions and additional flash photolysis nanosecond experiments on a mutant of cytochrome bd mostly lacking heme b595 allow to attribute the features in the well-known but unusual CO dissociation spectrum of cytochrome bd to individual heme d and heme b595 transitions. This renders it possible to compare the spectra of CO dissociation from reduced and mixed-valence cytochrome bd under static conditions and on a picosecond time scale in much more detail than previously possible. CO binding/dissociation from heme d is shown to perturb ferrous heme b595, causing induction/loss of an absorption band centered at ∼435 nm. In addition, the CO photodissociation-induced absorption changes at 50 ps reveal a bathochromic shift of ferrous heme b595 relative to the static spectrum. No evidence for transient binding of CO to heme b595 after dissociation from heme d is found in the picosecond time range. The yield of CO photodissociation from heme d on a time scale of < 15 ps is found to be diminished more than 3-fold when heme b595 is oxidized rather than reduced. In contrast to other known heme proteins, molecular oxygen cannot be photodissociated from the mixed-valence cytochrome bd at all, indicating a unique structural and electronic configuration of the diheme active site in the enzyme.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1654-1662 |
| Number of pages | 9 |
| Journal | Biochemistry |
| Volume | 41 |
| Issue number | 5 |
| DOIs | |
| State | Published - Feb 5 2002 |
| Externally published | Yes |
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- Biochemistry
Cite this
Interactions between heme d and heme b595 in quinol oxidase bd from Escherichia coli : A photoselection study using femtosecond spectroscopy. / Borisov, Vitaliy B.; Liebl, Ursula; Rappaport, Fabrice; Martin, Jean Louis; Zhang, Jie; Gennis, Robert B.; Konstantinov, Alexander A.; Vos, Marten H.
In: Biochemistry, Vol. 41, No. 5, 05.02.2002, p. 1654-1662.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Interactions between heme d and heme b595 in quinol oxidase bd from Escherichia coli
T2 - A photoselection study using femtosecond spectroscopy
AU - Borisov, Vitaliy B.
AU - Liebl, Ursula
AU - Rappaport, Fabrice
AU - Martin, Jean Louis
AU - Zhang, Jie
AU - Gennis, Robert B.
AU - Konstantinov, Alexander A.
AU - Vos, Marten H.
PY - 2002/2/5
Y1 - 2002/2/5
N2 - Femtosecond spectroscopy was performed on CO-liganded (fully reduced and mixed-valence states) and O2-liganded quinol oxidase bd from Escherichia coli. Substantial polarization effects, unprecedented for optical studies of heme proteins, were observed in the CO photodissociation spectra, implying interactions between heme d (the chlorin ligand binding site) and the close-lying heme b595 on the picosecond time scale; this general result is fully consistent with previous work [Vos, M. H., Borisov, V. B., Liebl, U., Martin, J.-L., and Konstantinov, A. A. (2000) Proc. Natl. Acad. Sci. U.S.A. 97, 1554-1559]. Analysis of the data obtained under isotropic and anisotropic polarization conditions and additional flash photolysis nanosecond experiments on a mutant of cytochrome bd mostly lacking heme b595 allow to attribute the features in the well-known but unusual CO dissociation spectrum of cytochrome bd to individual heme d and heme b595 transitions. This renders it possible to compare the spectra of CO dissociation from reduced and mixed-valence cytochrome bd under static conditions and on a picosecond time scale in much more detail than previously possible. CO binding/dissociation from heme d is shown to perturb ferrous heme b595, causing induction/loss of an absorption band centered at ∼435 nm. In addition, the CO photodissociation-induced absorption changes at 50 ps reveal a bathochromic shift of ferrous heme b595 relative to the static spectrum. No evidence for transient binding of CO to heme b595 after dissociation from heme d is found in the picosecond time range. The yield of CO photodissociation from heme d on a time scale of < 15 ps is found to be diminished more than 3-fold when heme b595 is oxidized rather than reduced. In contrast to other known heme proteins, molecular oxygen cannot be photodissociated from the mixed-valence cytochrome bd at all, indicating a unique structural and electronic configuration of the diheme active site in the enzyme.
AB - Femtosecond spectroscopy was performed on CO-liganded (fully reduced and mixed-valence states) and O2-liganded quinol oxidase bd from Escherichia coli. Substantial polarization effects, unprecedented for optical studies of heme proteins, were observed in the CO photodissociation spectra, implying interactions between heme d (the chlorin ligand binding site) and the close-lying heme b595 on the picosecond time scale; this general result is fully consistent with previous work [Vos, M. H., Borisov, V. B., Liebl, U., Martin, J.-L., and Konstantinov, A. A. (2000) Proc. Natl. Acad. Sci. U.S.A. 97, 1554-1559]. Analysis of the data obtained under isotropic and anisotropic polarization conditions and additional flash photolysis nanosecond experiments on a mutant of cytochrome bd mostly lacking heme b595 allow to attribute the features in the well-known but unusual CO dissociation spectrum of cytochrome bd to individual heme d and heme b595 transitions. This renders it possible to compare the spectra of CO dissociation from reduced and mixed-valence cytochrome bd under static conditions and on a picosecond time scale in much more detail than previously possible. CO binding/dissociation from heme d is shown to perturb ferrous heme b595, causing induction/loss of an absorption band centered at ∼435 nm. In addition, the CO photodissociation-induced absorption changes at 50 ps reveal a bathochromic shift of ferrous heme b595 relative to the static spectrum. No evidence for transient binding of CO to heme b595 after dissociation from heme d is found in the picosecond time range. The yield of CO photodissociation from heme d on a time scale of < 15 ps is found to be diminished more than 3-fold when heme b595 is oxidized rather than reduced. In contrast to other known heme proteins, molecular oxygen cannot be photodissociated from the mixed-valence cytochrome bd at all, indicating a unique structural and electronic configuration of the diheme active site in the enzyme.
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U2 - 10.1021/bi0158019
DO - 10.1021/bi0158019
M3 - Article
VL - 41
SP - 1654
EP - 1662
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 5
ER -