Coordination of Cu(B) in reduced and CO-liganded states of cytochrome bo3 from Escherichia coli. Is chloride ion a cofactor
Martina Ralle, Marina L. Verkhovskaya, Joel E. Morgan, Michael I. Verkhovsky, Mårten Wikström, Ninian J. Blackbur
Molecular & Medical Genetics
The ubiquinol oxidase cytochrome bo3 from Escherichia coli is one of the respiratory heme-copper oxidases which catalyze the reduction of O2 to water linked to translocation of protons across the bacterial or mitochondrial membrane. We have studied the structure of the Cu(B) site in the binuclear heme-copper center of O2 reduction by EXAFS spectroscopy in the fully reduced state of this enzyme, as well as in the reduced CO- liganded states where CO is bound either to the heme iron or to Cu(B). We find that, in the reduced enzyme, Cu(B) is coordinated by one weakly bound and two strongly bound histidine imidazoles at Cu-N distances of 2.10 and 1.92 Å, respectively, and that an additional feature at 2.54 Å is due to a highly ordered water molecule that might be weakly associated with the copper. Unexpectedly, the binding of CO to heme iron is found to result in a major conformational change at Cu(B), which now binds only two equidistant histidine imidazoles at 1.95 Å and a chloride ion at 2.25 Å, with elimination of the water molecule and one of the histidines. Attempts to remove the chloride from the enzyme by extensive dialysis did not change this finding, nor did substitution of chloride with bromide. Photolysis of CO bound to the heme iron is known to cause the CO to bind to Cu(B) in a very fast reaction and to remain bound to Cu(B) at low temperatures. In this state, we indeed find the CO to be bound to Cu(B) at a Cu-C distance of 1.85 Å, with chloride still bound at 2.25 Å and the two histidine imidazoles at a Cu-N distance of 2.01 Å. These results suggest that reduction of the binuclear site weakens the bond between Cu(B) and one of its three histidine imidazole ligands, and that binding of CO to the reduced binuclear site causes a major structural change in Cu(B) in which one histidine ligand is lost and replaced by a chloride ion. Whether chloride is a cofactor in this enzyme is discussed.
https://doi.org/10.1021/bi982885l
10.1021/bi982885l
Dive into the research topics of 'Coordination of Cu(B) in reduced and CO-liganded states of cytochrome bo3 from Escherichia coli. Is chloride ion a cofactor'. Together they form a unique fingerprint.
Cytochromes Medicine & Life Sciences 100%
Chlorides Medicine & Life Sciences 93%
Carbon Monoxide Medicine & Life Sciences 89%
Histidine Chemical Compounds 83%
Cofactor Chemical Compounds 80%
Cytochrome Chemical Compounds 75%
Heme Medicine & Life Sciences 69%
Ralle, M., Verkhovskaya, M. L., Morgan, J. E., Verkhovsky, M. I., Wikström, M., & Blackbur, N. J. (1999). Coordination of Cu(B) in reduced and CO-liganded states of cytochrome bo3 from Escherichia coli. Is chloride ion a cofactor. Biochemistry, 38(22), 7185-7194. https://doi.org/10.1021/bi982885l
Coordination of Cu(B) in reduced and CO-liganded states of cytochrome bo3 from Escherichia coli. Is chloride ion a cofactor. / Ralle, Martina; Verkhovskaya, Marina L.; Morgan, Joel E. et al.
In: Biochemistry, Vol. 38, No. 22, 01.06.1999, p. 7185-7194.
Ralle, M, Verkhovskaya, ML, Morgan, JE, Verkhovsky, MI, Wikström, M & Blackbur, NJ 1999, 'Coordination of Cu(B) in reduced and CO-liganded states of cytochrome bo3 from Escherichia coli. Is chloride ion a cofactor', Biochemistry, vol. 38, no. 22, pp. 7185-7194. https://doi.org/10.1021/bi982885l
Ralle M, Verkhovskaya ML, Morgan JE, Verkhovsky MI, Wikström M, Blackbur NJ. Coordination of Cu(B) in reduced and CO-liganded states of cytochrome bo3 from Escherichia coli. Is chloride ion a cofactor. Biochemistry. 1999 Jun 1;38(22):7185-7194. doi: 10.1021/bi982885l
Ralle, Martina ; Verkhovskaya, Marina L. ; Morgan, Joel E. et al. / Coordination of Cu(B) in reduced and CO-liganded states of cytochrome bo3 from Escherichia coli. Is chloride ion a cofactor. In: Biochemistry. 1999 ; Vol. 38, No. 22. pp. 7185-7194.
@article{e689dd01fc2146d1b97181c6329a5b3d,
title = "Coordination of Cu(B) in reduced and CO-liganded states of cytochrome bo3 from Escherichia coli. Is chloride ion a cofactor",
abstract = "The ubiquinol oxidase cytochrome bo3 from Escherichia coli is one of the respiratory heme-copper oxidases which catalyze the reduction of O2 to water linked to translocation of protons across the bacterial or mitochondrial membrane. We have studied the structure of the Cu(B) site in the binuclear heme-copper center of O2 reduction by EXAFS spectroscopy in the fully reduced state of this enzyme, as well as in the reduced CO- liganded states where CO is bound either to the heme iron or to Cu(B). We find that, in the reduced enzyme, Cu(B) is coordinated by one weakly bound and two strongly bound histidine imidazoles at Cu-N distances of 2.10 and 1.92 {\AA}, respectively, and that an additional feature at 2.54 {\AA} is due to a highly ordered water molecule that might be weakly associated with the copper. Unexpectedly, the binding of CO to heme iron is found to result in a major conformational change at Cu(B), which now binds only two equidistant histidine imidazoles at 1.95 {\AA} and a chloride ion at 2.25 {\AA}, with elimination of the water molecule and one of the histidines. Attempts to remove the chloride from the enzyme by extensive dialysis did not change this finding, nor did substitution of chloride with bromide. Photolysis of CO bound to the heme iron is known to cause the CO to bind to Cu(B) in a very fast reaction and to remain bound to Cu(B) at low temperatures. In this state, we indeed find the CO to be bound to Cu(B) at a Cu-C distance of 1.85 {\AA}, with chloride still bound at 2.25 {\AA} and the two histidine imidazoles at a Cu-N distance of 2.01 {\AA}. These results suggest that reduction of the binuclear site weakens the bond between Cu(B) and one of its three histidine imidazole ligands, and that binding of CO to the reduced binuclear site causes a major structural change in Cu(B) in which one histidine ligand is lost and replaced by a chloride ion. Whether chloride is a cofactor in this enzyme is discussed.",
author = "Martina Ralle and Verkhovskaya, {Marina L.} and Morgan, {Joel E.} and Verkhovsky, {Michael I.} and M{\aa}rten Wikstr{\"o}m and Blackbur, {Ninian J.}",
doi = "10.1021/bi982885l",
journal = "Biochemistry",
T1 - Coordination of Cu(B) in reduced and CO-liganded states of cytochrome bo3 from Escherichia coli. Is chloride ion a cofactor
AU - Ralle, Martina
AU - Verkhovskaya, Marina L.
AU - Morgan, Joel E.
AU - Verkhovsky, Michael I.
AU - Wikström, Mårten
AU - Blackbur, Ninian J.
N2 - The ubiquinol oxidase cytochrome bo3 from Escherichia coli is one of the respiratory heme-copper oxidases which catalyze the reduction of O2 to water linked to translocation of protons across the bacterial or mitochondrial membrane. We have studied the structure of the Cu(B) site in the binuclear heme-copper center of O2 reduction by EXAFS spectroscopy in the fully reduced state of this enzyme, as well as in the reduced CO- liganded states where CO is bound either to the heme iron or to Cu(B). We find that, in the reduced enzyme, Cu(B) is coordinated by one weakly bound and two strongly bound histidine imidazoles at Cu-N distances of 2.10 and 1.92 Å, respectively, and that an additional feature at 2.54 Å is due to a highly ordered water molecule that might be weakly associated with the copper. Unexpectedly, the binding of CO to heme iron is found to result in a major conformational change at Cu(B), which now binds only two equidistant histidine imidazoles at 1.95 Å and a chloride ion at 2.25 Å, with elimination of the water molecule and one of the histidines. Attempts to remove the chloride from the enzyme by extensive dialysis did not change this finding, nor did substitution of chloride with bromide. Photolysis of CO bound to the heme iron is known to cause the CO to bind to Cu(B) in a very fast reaction and to remain bound to Cu(B) at low temperatures. In this state, we indeed find the CO to be bound to Cu(B) at a Cu-C distance of 1.85 Å, with chloride still bound at 2.25 Å and the two histidine imidazoles at a Cu-N distance of 2.01 Å. These results suggest that reduction of the binuclear site weakens the bond between Cu(B) and one of its three histidine imidazole ligands, and that binding of CO to the reduced binuclear site causes a major structural change in Cu(B) in which one histidine ligand is lost and replaced by a chloride ion. Whether chloride is a cofactor in this enzyme is discussed.
AB - The ubiquinol oxidase cytochrome bo3 from Escherichia coli is one of the respiratory heme-copper oxidases which catalyze the reduction of O2 to water linked to translocation of protons across the bacterial or mitochondrial membrane. We have studied the structure of the Cu(B) site in the binuclear heme-copper center of O2 reduction by EXAFS spectroscopy in the fully reduced state of this enzyme, as well as in the reduced CO- liganded states where CO is bound either to the heme iron or to Cu(B). We find that, in the reduced enzyme, Cu(B) is coordinated by one weakly bound and two strongly bound histidine imidazoles at Cu-N distances of 2.10 and 1.92 Å, respectively, and that an additional feature at 2.54 Å is due to a highly ordered water molecule that might be weakly associated with the copper. Unexpectedly, the binding of CO to heme iron is found to result in a major conformational change at Cu(B), which now binds only two equidistant histidine imidazoles at 1.95 Å and a chloride ion at 2.25 Å, with elimination of the water molecule and one of the histidines. Attempts to remove the chloride from the enzyme by extensive dialysis did not change this finding, nor did substitution of chloride with bromide. Photolysis of CO bound to the heme iron is known to cause the CO to bind to Cu(B) in a very fast reaction and to remain bound to Cu(B) at low temperatures. In this state, we indeed find the CO to be bound to Cu(B) at a Cu-C distance of 1.85 Å, with chloride still bound at 2.25 Å and the two histidine imidazoles at a Cu-N distance of 2.01 Å. These results suggest that reduction of the binuclear site weakens the bond between Cu(B) and one of its three histidine imidazole ligands, and that binding of CO to the reduced binuclear site causes a major structural change in Cu(B) in which one histidine ligand is lost and replaced by a chloride ion. Whether chloride is a cofactor in this enzyme is discussed.
U2 - 10.1021/bi982885l
DO - 10.1021/bi982885l
JO - Biochemistry
JF - Biochemistry