The Pyoverdin Of Pseudomonas Fluorescens Btp2, A Novel Structural Type

Abstract—From Pseudomonas fluorescens BTP2 a pyoverdin was isolated which contained the so far not encountered Val in its peptide chain. Its structure could be elucidated by chemical degradation and spectroscopic data

Structure and characterization of isopyoverdin from Pseudomonas putida BTP1 and its relation to the biogenetic pathway leading to pyoverdins.

Pyoverdin type siderophores produced by six fluorescent Pseudomonas strains isolated from different rhizospheres were purified and characterized. The purified ferri-pyoverdins were tested for their ability to promote the growth of other strains grown under iron deficiency conditions. Only the one obtained from Pseudomonas putida BTP1 did not act as a growth promoter. The structure of the BTP1 siderophore was elucidated by spectroscopic methods and degradation studies. It turned out that it contains a chromophore which differs from the one typical for pyoverdins insofar as it carries the carboxyl group in 3- rather than in 1-position ((3S)-5-amino-1,2-dihydro-8,9-dihydroxy-3H-pyrimido[1,2a]quinoline-3- carboxylic acid). The amino group of the chromophore is substituted with the 5-carboxyl group of L-glutamic acid and its carboxyl group with the N-terminus of the peptide L-Asp-L-Ala-L-Asp-D-N5-Ac-N5-OH-Orn-L-Ser-L-c-N5-OH-Orn. This isopyoverdin fits into the biogenetic scheme which postulates ferribactins as the precursors of pyoverdins

Synthesis of the pyoverdin chromophore by a biomimetic oxidative cyclization

The fluorescent dihydropyrimido[1,2-a]quinoline chromophore of the pyoverdin siderophores has been synthesized by a biomimetic oxidative cyclization using an iodine(III) reagent, followed by elimination and dehydrogenation