title: Unsuspected control of siderophore production by N-acetylglucosamine in streptomycetes.
abstract: Iron is one of the most abundant elements on earth but is found in poorly soluble forms hardly accessible to microorganisms. To subsist, they have developed iron-chelating molecules called siderophores that capture this element in the environment and the resulting complexes are internalized by specific uptake systems. While biosynthesis of siderophores in many bacteria is regulated by iron availability and oxidative stress, we describe here a new type of regulation of siderophore production. We show that in Streptomyces coelicolor, their production is also controlled by N-acetylglucosamine (GlcNAc) via the direct transcriptional repression of the iron utilization repressor dmdR1 by DasR, the GlcNAc utilization regulator. This regulatory nutrient-metal relationship is conserved among streptomycetes, which indicates that the link between GlcNAc utilization and iron uptake repression, however unsuspected, is the consequence of a successful evolutionary process. We describe here the molecular basis of a novel inhibitory mechanism of siderophore production that is independent of iron availability. We speculate that the regulatory connection between GlcNAc and siderophores might be associated with the competition for iron between streptomycetes and their fungal soil competitors, whose cell walls are built from the GlcNAc-containing polymer chitin. Alternatively, GlcNAc could emanate from streptomycetes' own peptidoglycan that goes through intense remodelling throughout their life cycle, thereby modulating the iron supply according to specific needs at different stages of their developmental programme.
authors.affiliation: Centre for Protein Engineering, Université de Liège, Institut de chimie B6a, Liège B-4000, Belgium Walloon Centre for Industrial Biology, Université de Liège/Gembloux Agro-Bio Tech, Gembloux B-5030, Belgium Institute of Biotechnology of Léon, INBIOTEC, Parque Cientifico de Léon, Leon 24006, Spain Microbial Development, Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300RA Leiden, the Netherlands.
authors.forename: Matthias
authors.initials: M
authors.lastname: Craig
authors.forename: Stéphany
authors.initials: S
authors.lastname: Lambert
authors.forename: Samuel
authors.initials: S
authors.lastname: Jourdan
authors.forename: Elodie
authors.initials: E
authors.lastname: Tenconi
authors.forename: Séverine
authors.initials: S
authors.lastname: Colson
authors.forename: Marta
authors.initials: M
authors.lastname: Maciejewska
authors.forename: Marc
authors.initials: M
authors.lastname: Ongena
authors.forename: Juan Francisco
authors.initials: JF
authors.lastname: Martin
authors.forename: Gilles
authors.initials: G
authors.lastname: van Wezel
authors.forename: Sébastien
authors.initials: S
authors.lastname: Rigali