The structure of the pyoverdin isolated from various Pseudomonas syringae pathovars

From seven different pathovars of Pseudomonas syringae representing various genetic subgroups, and one strain of Pseudomonas viridiflava the same pyov erdin siderophore (1) was isolated, probably identical with the pyoverdin w hose amino acid composition (but not their sequence) had been reported befo re. I is the first pyoverdin where two of the ligands for Fe3+ are beta -hy droxy Asp units. Its remarkably high complexing constant for Fe3+ at pH 5 a s compared with other pyoverdins offers a definite advantage in plant infec tion. The structure elucidation of I will be described and the taxonomical implications regarding pyoverdins with different structures ascribed previo usly to R syringae strains will be discussed.