The superfamily of heme-copper respiratory oxidases

Garcı́a-Horsman, J. Arturo; Barquera, Blanca; Rumbley, Jon N.; Ma, Jixiang; Gennis, Robert B.

doi:10.1128/jb.176.18.5587-5600.1994

Cited by 440 publications

(458 citation statements)

References 130 publications

(73 reference statements)

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“…heme o and CuB and plays a central role of dioxygen reduction and proton pumping [6,7]. Recent site-directed mutagenesis studies revealed a molecular structure of the heme o-CuB binuclear center [6,7] and a possible mechanism for the facilitated heme b-to-heme o electron transfer [6,8].…”

Section: Introductionmentioning

confidence: 99%

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Stabilization of a semiquinone radical at the high‐affinity quinone‐binding site (Q_H) of the Escherichia coli bo‐type ubiquinol oxidase

et al. 1995

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Reaction of ubiquinone in the high-affinity quinonebinding site (QH) in bo-type ubiquinol oxidase from Escherichia coli was revealed by EPR and optical studies. In the Qn site, ubiquinol was shown to be oxidized to ubisemiquinone and to ubiquinone, while no semiquinone signal was detected in the oxidase isolated from mutant cells that cannot synthesize ubiquinone. The Qn site highly stabilized ubisemiquinone radical with a stability constant of 1-4 at pH 8.5 and the stability became lower at the lower pH. Midpoint potential of QH21Q couple was -2 mV at pH 8.5 and showed -60 mVIpH dependence indicative of 2H÷/2e -reaction. The Em was more negative than that of low-spin heme b above pH 7.0. We conclude that the Qn mediates intramolecular electron transfer from ubiquinol in the low-affinity quinol oxidation site (QL) to low-spin heme b. Unique roles of the quinone-binding sites in the bacterial ubiquinoi oxidase are discussed.

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Section: Introductionmentioning

confidence: 99%

“…Recent site-directed mutagenesis studies revealed a molecular structure of the heme o-CuB binuclear center [6,7] and a possible mechanism for the facilitated heme b-to-heme o electron transfer [6,8]. Based on photoaffinity cross-linking experiments, a quinone-binding site(s) has been assigned to reside in subunit II [9].…”

Section: Introductionmentioning

confidence: 99%

Stabilization of a semiquinone radical at the high‐affinity quinone‐binding site (Q_H) of the Escherichia coli bo‐type ubiquinol oxidase

et al. 1995

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“…It belongs to the so-called super-family of heme-copper oxidases [3] and is encoded by the fixNOQP operon [1]. The purified oxidase contains at least three subunits [4].…”

Section: Introductionmentioning

confidence: 99%

“…FixN is an integral membrane protein with up to 14 putative transmembrane a-helices [1,2]. It contains a low-and a highspin heine B cofactor, the latter being associated with copper (CUB) in a binuclear center that is the catalytic site of oxygen reduction [3,4,6,7].…”

Section: Introductionmentioning

confidence: 99%

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Histidine 131, not histidine 43, of the Bradyrhizobium japonicum FixN protein is exposed towards the periplasm and essential for the function of the cbb₃‐type cytochrome oxidase

1996

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In subunit I (FixN) of the Bradyrhizobiumjaponicum cbb3-type oxidase, only five instead of the normal six strictly conserved histidines (H) could be unambiguously assigned as the putative heme or copper ligands. The ambiguity concerned H43 or H131 as the presumptive N-terminal ligands of the low-spin heme B. We report here that a H43A replacement had a wildtype phenotype, whereas the H131A mutant was defective in oxidase function and suhunlt assembly or stability, suggesting that H131 serves as the N-terminal low-spin heine ligand. Topological studies revealed that H131 resides on the periplasmic side of helix 2, where one of the low-spin heme ligands is normally found in conventional heme-copper oxidases.

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Functional diversity within the mitochondrial electron transport chain of plant pathogenic fungi

Joseph‐Horne

Hollomon

2000

Pest. Manag. Sci.

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Mitochondrial transfer of electrons from NAD(P)H or FADH2 to the terminal electron acceptor, oxygen, follows a highly complex scheme, involving numerous redox components. Whilst electron transfer has been extensively studied over past decades in mammalian, plant and some fungal species, relatively little is known about the respiratory chain of phytopathogenic fungi. The recent identification of the electron transport chain as a viable target for effective control of fungal infections has contributed to a significantly increased research effort into this area of fungal biochemistry. A striking feature of the electron transport chain within phytopathogenic fungi is the presence of components not found in the classical (mammalian) chain. Recent research has suggested the presence of a plant‐like ‘alternative’ oxidase, internal and external NAD(P)H dehydrogenases, and cyanide‐insensitive cytochrome c oxidases. In this mini‐review on electron transport in phytopathogenic fungi, the current status of research into the function and expression characteristics of these ‘alternative’ redox centres is discussed. © 2000 Society of Chemical Industry

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The superfamily of heme-copper respiratory oxidases

Cited by 440 publications

References 130 publications

Stabilization of a semiquinone radical at the high‐affinity quinone‐binding site (Q_H) of the Escherichia coli bo‐type ubiquinol oxidase

Stabilization of a semiquinone radical at the high‐affinity quinone‐binding site (Q_H) of the Escherichia coli bo‐type ubiquinol oxidase

Histidine 131, not histidine 43, of the Bradyrhizobium japonicum FixN protein is exposed towards the periplasm and essential for the function of the cbb₃‐type cytochrome oxidase

Functional diversity within the mitochondrial electron transport chain of plant pathogenic fungi

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The superfamily of heme-copper respiratory oxidases

Cited by 440 publications

References 130 publications

Stabilization of a semiquinone radical at the high‐affinity quinone‐binding site (QH) of the Escherichia coli bo‐type ubiquinol oxidase

Stabilization of a semiquinone radical at the high‐affinity quinone‐binding site (QH) of the Escherichia coli bo‐type ubiquinol oxidase

Histidine 131, not histidine 43, of the Bradyrhizobium japonicum FixN protein is exposed towards the periplasm and essential for the function of the cbb3‐type cytochrome oxidase

Functional diversity within the mitochondrial electron transport chain of plant pathogenic fungi

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Stabilization of a semiquinone radical at the high‐affinity quinone‐binding site (Q_H) of the Escherichia coli bo‐type ubiquinol oxidase

Stabilization of a semiquinone radical at the high‐affinity quinone‐binding site (Q_H) of the Escherichia coli bo‐type ubiquinol oxidase

Histidine 131, not histidine 43, of the Bradyrhizobium japonicum FixN protein is exposed towards the periplasm and essential for the function of the cbb₃‐type cytochrome oxidase