Quinolobactin, a new siderophore of Pseudomonas fluorescens ATCC 17400, the production of which is repressed by the cognate pyoverdine

• Published in: Applied and environmental microbiology 2000-02, Vol.66 (2), p.487-492
• Main Authors: MOSSIALOS, D, MEYER, J.-M, BUDZIKIEWICZ, H, WOLFF, U, KOEDAM, N, BAYSSE, C, ANJAIAH, V, CORNELIS, P
• Format: Article
• Language: English
• Subjects: Bacterial Outer Membrane Proteins - biosynthesis; Bacterial Outer Membrane Proteins - chemistry; Bacterial Outer Membrane Proteins - metabolism; Bacteriology; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; Culture Media - chemistry; DNA Transposable Elements; Electrophoresis, Polyacrylamide Gel; Fundamental and applied biological sciences. Psychology; Immunology; IROMP protein; Iron - metabolism; Microbiology; Mission oriented research; Mutagenesis, Insertional; Mutation; Oligopeptides; Permeability, membrane transport, intracellular transport; Physiology and Biotechnology; Physiology and metabolism; Pigments, Biological - metabolism; Pigments, Biological - pharmacology; Pseudomonas fluorescens; Pseudomonas fluorescens - drug effects; Pseudomonas fluorescens - genetics; Pseudomonas fluorescens - growth & development; Pseudomonas fluorescens - metabolism; Pyoverdine; Quinolines; Quinolobactin; Siderophores - biosynthesis
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.66.2.487-492.2000

Transposon mutant strain 3G6 of Pseudomonas fluorescens ATCC 17400 which was deficient in pyoverdine production, was found to produce another iron-chelating molecule; this molecule was identified as 8-hydroxy-4-methoxy-quinaldic acid (designated quinolobactin). The pyoverdine-deficient mutant produced a supplementary 75-kDa iron-repressed outer membrane protein (IROMP) in addition to the 85-kDa IROMP present in the wild type. The mutant was also characterized by substantially increased uptake of (59)Fe-quinolobactin. The 75-kDa IROMP was produced by the wild type after induction by quinolobactin-containing culture supernatants obtained from the pyoverdine-negative mutant or by purified quinolobactin. Conversely, adding purified wild-type pyoverdine to the growth medium resulted in suppression of the 75-kDa IROMP in the pyoverdine-deficient mutant; however, suppression was not observed when Pseudomonas aeruginosa PAO1 pyoverdine, a siderophore utilized by strain 3G6, was added to the culture. Therefore, we assume that the quinolobactin receptor is the 75-kDa IROMP and that the quinolobactin-mediated iron uptake system is repressed by the cognate pyoverdine.