ph-dependent structural changes at the heme-copper binuclear center of cytochrome c oxidase

Tapan Kanti Das, Farol L. Tomson, Robert B. Gennis, Michael Gordon, Denis L. Rousseau

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

The resonance Raman spectra of the aa3 cytochrome c oxidase from Rhodobacter sphaeroides reveal pH-dependent structural changes in the binuclear site at room temperature. The binuclear site, which is the catalytic center of the enzyme, possesses two conformations at neutral pH, assessed from their distinctly different Fe-CO stretching modes in the resonance Raman spectra of the CO complex of the fully reduced enzyme. The two conformations (α and β) interconvert reversibly in the pH 6-9 range with a pKa of 7.4, consistent with Fourier transform infrared spectroscopy measurements done at cryogenic temperatures (D. M. Mitchell, J. P. Shapleigh, A. M. Archer, J. O. Alben, and R. B. Gennis, 1996, Biochemistry 35:9446-9450). It is postulated that the different structures result from a change in the position of the CuB atom with respect to the CO due to the presence of one or more ionizable groups in the vicinity of the binuclear center. The conserved tyrosine residue (Tyr-288 in R. sphaeroides, Tyr-244 in the bovine enzyme) that is adjacent to the oxygen-binding pocket or one of the histidines that coordinate CuB are possible candidates. The existence of an equilibrium between the two conformers at physiological pH and room temperature suggests that the conformers may be functionally involved in enzymatic activity.

Original languageEnglish (US)
Pages (from-to)2039-2045
Number of pages7
JournalBiophysical Journal
Volume80
Issue number5
StatePublished - 2001

Fingerprint

Electron Transport Complex IV
Heme
Copper
Carbon Monoxide
Rhodobacter sphaeroides
Temperature
Enzymes
Fourier Transform Infrared Spectroscopy
Histidine
Biochemistry
Tyrosine
Oxygen

ASJC Scopus subject areas

  • Biophysics

Cite this

ph-dependent structural changes at the heme-copper binuclear center of cytochrome c oxidase. / Das, Tapan Kanti; Tomson, Farol L.; Gennis, Robert B.; Gordon, Michael; Rousseau, Denis L.

In: Biophysical Journal, Vol. 80, No. 5, 2001, p. 2039-2045.

Research output: Contribution to journalArticle

Das, TK, Tomson, FL, Gennis, RB, Gordon, M & Rousseau, DL 2001, 'ph-dependent structural changes at the heme-copper binuclear center of cytochrome c oxidase', Biophysical Journal, vol. 80, no. 5, pp. 2039-2045.
Das, Tapan Kanti ; Tomson, Farol L. ; Gennis, Robert B. ; Gordon, Michael ; Rousseau, Denis L. / ph-dependent structural changes at the heme-copper binuclear center of cytochrome c oxidase. In: Biophysical Journal. 2001 ; Vol. 80, No. 5. pp. 2039-2045.
@article{a6153c76f7f641bcab52d3f493dbcaaa,
title = "ph-dependent structural changes at the heme-copper binuclear center of cytochrome c oxidase",
abstract = "The resonance Raman spectra of the aa3 cytochrome c oxidase from Rhodobacter sphaeroides reveal pH-dependent structural changes in the binuclear site at room temperature. The binuclear site, which is the catalytic center of the enzyme, possesses two conformations at neutral pH, assessed from their distinctly different Fe-CO stretching modes in the resonance Raman spectra of the CO complex of the fully reduced enzyme. The two conformations (α and β) interconvert reversibly in the pH 6-9 range with a pKa of 7.4, consistent with Fourier transform infrared spectroscopy measurements done at cryogenic temperatures (D. M. Mitchell, J. P. Shapleigh, A. M. Archer, J. O. Alben, and R. B. Gennis, 1996, Biochemistry 35:9446-9450). It is postulated that the different structures result from a change in the position of the CuB atom with respect to the CO due to the presence of one or more ionizable groups in the vicinity of the binuclear center. The conserved tyrosine residue (Tyr-288 in R. sphaeroides, Tyr-244 in the bovine enzyme) that is adjacent to the oxygen-binding pocket or one of the histidines that coordinate CuB are possible candidates. The existence of an equilibrium between the two conformers at physiological pH and room temperature suggests that the conformers may be functionally involved in enzymatic activity.",
author = "Das, {Tapan Kanti} and Tomson, {Farol L.} and Gennis, {Robert B.} and Michael Gordon and Rousseau, {Denis L.}",
year = "2001",
language = "English (US)",
volume = "80",
pages = "2039--2045",
journal = "Biophysical Journal",
issn = "0006-3495",
publisher = "Biophysical Society",
number = "5",

}

TY - JOUR

T1 - ph-dependent structural changes at the heme-copper binuclear center of cytochrome c oxidase

AU - Das, Tapan Kanti

AU - Tomson, Farol L.

AU - Gennis, Robert B.

AU - Gordon, Michael

AU - Rousseau, Denis L.

PY - 2001

Y1 - 2001

N2 - The resonance Raman spectra of the aa3 cytochrome c oxidase from Rhodobacter sphaeroides reveal pH-dependent structural changes in the binuclear site at room temperature. The binuclear site, which is the catalytic center of the enzyme, possesses two conformations at neutral pH, assessed from their distinctly different Fe-CO stretching modes in the resonance Raman spectra of the CO complex of the fully reduced enzyme. The two conformations (α and β) interconvert reversibly in the pH 6-9 range with a pKa of 7.4, consistent with Fourier transform infrared spectroscopy measurements done at cryogenic temperatures (D. M. Mitchell, J. P. Shapleigh, A. M. Archer, J. O. Alben, and R. B. Gennis, 1996, Biochemistry 35:9446-9450). It is postulated that the different structures result from a change in the position of the CuB atom with respect to the CO due to the presence of one or more ionizable groups in the vicinity of the binuclear center. The conserved tyrosine residue (Tyr-288 in R. sphaeroides, Tyr-244 in the bovine enzyme) that is adjacent to the oxygen-binding pocket or one of the histidines that coordinate CuB are possible candidates. The existence of an equilibrium between the two conformers at physiological pH and room temperature suggests that the conformers may be functionally involved in enzymatic activity.

AB - The resonance Raman spectra of the aa3 cytochrome c oxidase from Rhodobacter sphaeroides reveal pH-dependent structural changes in the binuclear site at room temperature. The binuclear site, which is the catalytic center of the enzyme, possesses two conformations at neutral pH, assessed from their distinctly different Fe-CO stretching modes in the resonance Raman spectra of the CO complex of the fully reduced enzyme. The two conformations (α and β) interconvert reversibly in the pH 6-9 range with a pKa of 7.4, consistent with Fourier transform infrared spectroscopy measurements done at cryogenic temperatures (D. M. Mitchell, J. P. Shapleigh, A. M. Archer, J. O. Alben, and R. B. Gennis, 1996, Biochemistry 35:9446-9450). It is postulated that the different structures result from a change in the position of the CuB atom with respect to the CO due to the presence of one or more ionizable groups in the vicinity of the binuclear center. The conserved tyrosine residue (Tyr-288 in R. sphaeroides, Tyr-244 in the bovine enzyme) that is adjacent to the oxygen-binding pocket or one of the histidines that coordinate CuB are possible candidates. The existence of an equilibrium between the two conformers at physiological pH and room temperature suggests that the conformers may be functionally involved in enzymatic activity.

UR - http://www.scopus.com/inward/record.url?scp=0035042514&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035042514&partnerID=8YFLogxK

M3 - Article

C2 - 11325707

AN - SCOPUS:0035042514

VL - 80

SP - 2039

EP - 2045

JO - Biophysical Journal

JF - Biophysical Journal

SN - 0006-3495

IS - 5

ER -