Affinity-Labeling of an NADPH-Binding Site on the Heavy Subunit of Flavocytochrome b558 in Particulate NADPH Oxidase from Activated Human Neutrophils

Ravel, Pascale; Lederer, Florence

doi:10.1006/bbrc.1993.2284

Cited by 27 publications

(14 citation statements)

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“…The NADPH-and FAD-binding sites of flavocytochrome b 558 are localized in the gp91phox subunit, as demonstrated by photolabeling with photoactivatable azido derivatives of NADPH [96,106] and FAD [95] and also by affinity labeling, using pyridoxal-5¢-diphospho-5-adenosine [107,108]. The crystal structure of several NADPH-dependent flavoproteins is known, and the regions of their polypeptide chains that participate in binding NADPH and FAD have been characterized.…”

Section: Mapping Of Nadph Fad and Heme-binding Sites In The Gp91phoxmentioning

confidence: 98%

The superoxide-generating NADPH oxidase: structural aspects and activation mechanism

Vignais¹

2002

Cellular and Molecular Life Sciences (CMLS)

698

597

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Flavocytochrome b558 is the catalytic core of the respiratory-burst oxidase, an enzyme complex that catalyzes the NADPH-dependent reduction of O2 into the superoxide anion O2 in phagocytic cells. Flavocytochrome b558 is anchored in the plasma membrane. It is a heterodimer that consists of a large glycoprotein gp91phox (phox forphagocyte oxidase) (beta subunit) and a small protein p22phox (alpha subunit). The other components of the respiratory-burst oxidase are water-soluble proteins of cytosolic origin, namely p67phox, p47phox, p40phox and Rac. Upon cell stimulation, they assemble with the membrane-bound flavocytochrome b558 which becomes activated and generates O2-. A defect in any of the genes encoding gp91phox, p22phox, p67phox or p47phox results in chronic granulomatous disease, a genetic disorder characterized by severe and recurrent infections, illustrating the role of O2- and the derived metabolites H2O2 and HOCl in host defense against invading microorganisms. The electron carriers, FAD and hemes b, and the binding site for NADPH are confined to the gp91phox subunit of flavocytochrome b558. The p22phox subunit serves as a docking site for the cytoso lic phox proteins. This review provides an overview of current knowledge on the structural organization of the O2(-)-generating flavocytochrome b558, its kinetics, its mechanism of activation and the regulation of its biosynthesis. Homologues of gp91phox, called Nox and Duox, are present in a large variety of non-phagocytic cells. They exhibit modest O2(-)-generating oxidase activity, and some act as proton channels. Their role in various aspects of signal transduction is currently under investigation and is briefly discussed.

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Section: Mapping Of Nadph Fad and Heme-binding Sites In The Gp91phoxmentioning

confidence: 98%

The superoxide-generating NADPH oxidase: structural aspects and activation mechanism

Vignais¹

2002

Cellular and Molecular Life Sciences (CMLS)

698

597

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“…In a cellfree system, AA increased the affinity of NADPH for the NADPH oxidase complex about five-fold [203]. Ravel and Lederer [204] proposed that assembly of cytosolic components with cytochrome b 558 results in a conformational change that greatly increases the affinity of the enzyme for NADPH. Recent evidence suggests a conformational change in cytochrome b 558 that initiates electron transfer from NADPH [83], although not necessarily one that changes NADPH affinity.…”

Section: Changes In Affinity Of the Nadph Oxidase Complex For Nadphmentioning

confidence: 99%

Regulation and termination of NADPH oxidase activity

DeCoursey

Ligeti

2005

Cell. Mol. Life Sci.

226

190

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NADPH oxidase of phagocytes plays a crucial role in host defense by producing reactive oxygen species (ROS) that are intended to kill invading microbes. Many other cells produce ROS for signaling purposes. The respiratory burst oxidase in human neutrophils is the main but not exclusive subject of this review, because it is archetypical and has been studied most extensively. The activity of this enzyme must be controlled in phagocytes to prevent collateral damage, and in non-phagocytic cells to perform its signaling role. With many stimuli, NADPH oxidase activity is transient. Various forms of evidence indicate that sustained NADPH oxidase activity requires continuous renewal of the enzyme complex, without which rapid deactivation occurs. This review considers mechanisms that have been proposed to terminate the phagocyte respiratory burst. Changes in the phosphorylation state of p47(phox) and in the species of nucleotide bound to Rac seem to be the dominant factors in deactivation.

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“…[99][100][101] The relationship between these two NADPH-binding sites has not been determined, although notably, cyt b 558 alone catalyzes active O 2 2 production using NADPH as a reductant. 40 The reduced interaction of mutated p67 phox with Rac and impaired translocation of the cytosolic oxidase complex in the activated phagocytes of CGD patients have recently been reported.…”

Section: Cytosolic Components Of the Oxidasementioning

confidence: 99%

NADPH oxidases: an overview from structure to innate immunity-associated pathologies

et al. 2014

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Affinity-Labeling of an NADPH-Binding Site on the Heavy Subunit of Flavocytochrome b558 in Particulate NADPH Oxidase from Activated Human Neutrophils

Cited by 27 publications

References 0 publications

The superoxide-generating NADPH oxidase: structural aspects and activation mechanism

The superoxide-generating NADPH oxidase: structural aspects and activation mechanism

Regulation and termination of NADPH oxidase activity

NADPH oxidases: an overview from structure to innate immunity-associated pathologies

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