Iron release from ferrisiderophores

A multi-step mechanism involving a NADH/FMN oxidoreductase and a chemical reduction by FMNH2

Authors

  • Félix HALLÉ,

    1. Laboratoire de Microbiologie, Unité de Recherche Associée au Centre National de la Recherche Scientifique, no. 1481, Université Louis Pasteur, Strasbourg, France
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  • Jean-Marie MEYER

    Corresponding author
    1. Laboratoire de Microbiologie, Unité de Recherche Associée au Centre National de la Recherche Scientifique, no. 1481, Université Louis Pasteur, Strasbourg, France
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  • Note. This article is dedicated to the memory of Thomas Emery.

Correspondence to J. M. Meyer, Laboratoire de Microbiologie, ULP, Institut Le Bel, 4 rue Blaise-Pascal, F-67070 Strasbourg, France
Fax: + 3388607550.

Abstract

Release of iron from various ferrisiderophores (ferripyoverdines, ferrioxamines B and E, ferricrocin, ferrichrome A, ferrienterobactin and its analog ferric N,N′,N”-tri(1,3,5-Tris) 2,3-dihydroxybenzoylaminomethylbenzene) was obtained through an enzymic reduction of iron, involving NADH, FMN and the ferripyoverdine reductase of Pseudomonas aeruginosa PAO1. The iron released from the same complexes was also obtained through chemical reduction of iron involving FMNH2. Evidence is given that the enzymic process acts through a FMNH2 reduction; the P. aeruginosa enzyme, purified according to its ferripyoverdine-reductase activity [Hallé, F. & Meyer, J. M., Eur. J. Biochem. 209, 613–620], functions as a NADH:FMN oxidoreductase, the FMNH2 produced being able to chemically reduce the iron complexed by siderophores. The general occurence of such a multi-step mechanism, which denies the existence of specific ferrisiderophore reductases, is discussed.

Abbreviations
MECAM

N,N′,N”-tri(1,3,5-Tris) 2,3-dihydroxy-benzoylaminomethylbenzene

MECAMS

N,N′,N”-tri(1,3,5-Tris) 2,3-dihydroxy-5-sulfobenzoyltriaminomethylbenzene

Enzymes
 

Ferripyoverdine reductase (EC 1.6.99.–)

 

NADH: FMN oxidoreductase (EC 1.6.8.1)

Ancillary