Structure of pseudobactin 7SR1, a siderophore from a plant-deleterious Pseudomonas.
When grown in iron-limiting culture medium, sugar beet deleterious Pseudomonas 7SR1 produced extra-cellularly the yellow-green, fluorescent siderophore pseudobactin 7SR1. Pseudobactin 7SR1 had a molecular formula of C46H63N13O23 and a molecular mass of 1166 g/mol. Pseudobactin 7SR1 contained a cyclic octapeptide with the amino acid sequence L-Ala-Gly-Ser-Ser-threo-beta-OH-Asp-Thr-Ser-N delta-OH-Orn. Since pseudobactin 7SR1 was not affected by nonspecific enzymes, it might contain D-amino acids. A yellow-green, fluorescent quinoline derivative is postulated to be attached via an ester bond to the serine residue following the glycine. A malamide group was attached to carbon 3 of the quinoline derivative. The three bidentate iron(III)-chelating groups consisted of an alpha-hydroxy acid group derived from beta-hydroxyaspartic acid, an omicron-dihydroxy aromatic group derived from the yellow-green, fluorescent chromophore, and a hydroxamate group derived from N delta-acetyl-N delta-hydroxyornithine. The chemical structure of pseudobactin 7SR1 is remarkably similar to that of pseudobactin, the siderophore of plant growth promoting Pseudomonas B10.
D000595:Amino Acid Sequence; D007476:Ionophores / Q000302:isolation & purification*; D007501:Iron / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009842:Oligopeptides / Q000302:isolation & purification*; D010935:Plant Diseases; D011549:Pseudomonas / Q000032:analysis* / Q000472:pathogenicity
D007476:Ionophores; D009842:Oligopeptides; C042563:pseudobactin 7SR1; D007501:Iron