Production of the triacetecholate siderophore protochelin byAzotobacter vinelandii

✍ Scribed by Anthony S. Cornish; William J. Page

• Publisher: Springer Netherlands
• Year: 1995
• Tongue: English
• Weight: 665 KB
• Volume: 8
• Category: Article
• ISSN: 1572-8773
• DOI: 10.1007/bf00141607

✦ Synopsis

Azotobacter vinelandii grown in iron-limited medium containing 1 tiM molybdate released the catecholate siderophores azotochelin and aminochelin [bis(2,3-dihydroxybenzoyl-lysine) and 2,3-dihydroxybenzoyl-putrescine, respectively] into the culture fluid. However these catecholates were not observed when the medium contained 1 mM molybdate, but were replaced by another catecholate compound. The appearance of this new compound was not an artifact of extraction of the catecholates from the culture fluid in the presence of high molybdate. Full and partial acid hydrolysis and fast atom bombardment mass spectroscopy showed that the new compound was the tricatecholate protochelin, a product of the condensation of azotochelin and aminochelin. The production of protochelin was iron-repressible and protochelin very rapidly decolorized the Chrome AzuroI-S assay. Protochelin promoted the growth of the siderophore-deficient A. vinelandii strain PI00 under iron-restricted conditions and promoted 55Fe uptake into iron-limited cells, confirming that protochelin can be used as a siderophore by A. vinelandii.