Bacterial Constituents, XXXVII. Pyoverdin‐Type Siderophores from Pseudomonas aeruginosa

The structures of pyoverdin C, D, and E isolated from the culture medium of Pseudomonas aeruginosa (which are identical with the pyoverdins PaB, PaA, and Pa6–8)) have been elucidated by spectroscopic methods and degradation studies. The pyoverdins consist of a chromophore which could be identified as (1S)‐5‐amino‐2,3‐dihydro‐8,9‐dihydroxy‐1H‐pyrimido[1,2‐a]quinoline‐1‐carboxylic acid substituted at the amino group with a 4‐carboxy‐4‐oxobutanoyl (C), a 3‐carboxypropanoyl (D) or a succinamoyl residue (E) and at the carboxy group with the N‐terminus of D‐Ser‐L‐Arg‐D‐Ser‐L‐Orn(N5‐OH‐N5‐CHO)‐L‐Lys‐L‐Orn(N5‐OH‐N5‐CHO)‐L‐Thr‐L‐Thr]. In an appendix a tentative nomenclature for pyoverdin‐type compounds is proposed.