NEW PYOVERDIN SIDEROPHORES FROM PSEUDOMONAS-PUTIDA C

Four new pyoverdins (C 2 A, C 2 B, C 3 A, C 3 B) were isolated from cultures of Pseudomonas putida C. Their structures were elucidated by chemical and spectroscopic methods. The compounds consist of a chromophore - (IS)-5-amino-2,3-dihydro-8,9-di-hydroxy-1H-pyrimido[1,2-a]quinoline-1-carboxylic acid - substituted at the amino group with a dicarboxylic acid or its amide. The carboxyl group of the chromophore is amidically bound to the N-terminus of L-Asp-D-[N5-hydroxy-N5-(D-beta-hydroxybutyryl)] Orn-D-Dab-L-Thr-Gly-D-Ser-L-Ser-L-threo-beta-hydroxy-Asp-L-Thr. The four pyoverdins differ only in the nature of the dicarboxylic acid (amide), viz. L-malamoyl- (C 2 A), succinamoyl- (C 2 B), L-3-carboxy-2-hydroxypropanoyl- (C 3 A) or 3-carboxy-propanoyl (C 3 B) residue. The hydroxamate function consists of N5-hydroxy-Orn and beta-hydroxybutyric acid, a structural unit which has been encountered for the first time in a pyoverdin.