title: Characterization of anguibactin, a novel siderophore from Vibrio anguillarum 775(pJM1).
abstract: Anguibactin, a siderophore produced by cells of Vibrio anguillarum 775 harboring the pJM1 plasmid, has now been isolated from the supernatants of iron-deficient cultures. This iron-reactive material was purified by adsorption onto an XAD-7 resin and subsequent gel filtration on a Sephadex LH-20 column. The resulting neutral compound produced an ion at m/z 348 in mass spectrometry and contained one sulfur, four oxygen, and four nitrogen atoms as determined by elemental analysis. Its strong UV absorbance and blue fluorescence were suggestive of a phenolic moiety. In colorimetric reactions anguibactin behaved like a catechol. The catechol assignment was supported by the appearance of a new absorption band at 510 nm in the ferric complex and by the appearance of peaks at 1,367, 1,447, 1,469, and 1,538 cm-1 in the resonance Raman spectrum. In addition, the infrared spectrum gave evidence of a secondary amide function, but no free carboxylic acid or hydroxamic acid groups were observed. A third iron-ligating group was suggested by the liberation of three protons during iron binding; mass spectrometry of the resulting material yielded a molecular ion characteristic of a 1:1 complex of ferric anguibactin. The purified anguibactin exhibited specific growth-promoting activity under iron-limiting conditions for a siderophore-deficient mutant of V. anguillarum 775(pJM1). A novel structure for anguibactin was indicated by the failure of a large number of known siderophores and synthetic chelators to yield a similar type of specific cross-feeding in the V. anguillarum bioassay.
mesh_terms: D001425:Bacterial Outer Membrane Proteins; D055598:Chemical Phenomena; D002621:Chemistry; D003124:Colorimetry; D004586:Electrophoresis; D007502:Iron Chelating Agents / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D010455:Peptides; D011956:Receptors, Cell Surface / Q000378:metabolism; D017262:Siderophores; D013057:Spectrum Analysis; D014733:Vibrio / Q000032:analysis*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D007502:Iron Chelating Agents; D010455:Peptides; D011956:Receptors, Cell Surface; D017262:Siderophores; C035902:siderophore receptors; C049469:anguibactin