Structures of two polyamine-containing catecholate siderophores from vibrio fluvialis

From low-iron cultures of Vibrio fluvialis AQ 0012, two new compounds with siderophore activity were purified by XAD-7 adsorption followed by preparative TLC. Norspermidine and 2,3-dihydroxybenzoic acid were identified as constituents common to both compounds by GC-MS analyses of their acid hydrolytic products. In addition, L-threonine was identified in the hydrolysate of one compound, named fluvibactin. Based on high magnetic NMR analyses, the structure of fluvibactin was established as iV4-[2-(2,3-dihydroxyphenyl)- ftra/is-5-methyl-2-oxa2oline-4-yl]carboxy-iV1, iV7-6is-(2,3-dihydroxybenzoyl)- norspermidine, and that of the other compound as iV, iV7-w-(2,3-dihydroxybenzoyl)- norspermidine. The structures were supported by fast atom bombardment mass spectrometry. Both of the purified compounds restored growth inhibition of the producer strain and V. cholerae Non-01 induced by ethylenediamine di-(o-hydroxyphenylacetic acid), a potent synthetic chelating agent of ferric iron. 1993