Synthesis and iron-binding properties of quinolobactin, a siderophore from a pyoverdine-deficient Pseudomonas fluorescens.
Quinolobactin is a new siderophore produced by a pyoverdine deficient mutant of Pseudomonas fluorescens. A simple and efficient synthesis of quinolobactin is described, starting from xanthurenic acid. The protonation constants of quinolobactin were determined by potentiometric titrations as pKa2 = 5.50+/-0.07, pKa1 = 10.30+/-0.05. The equilibria of the metal complexes were studied by means of spectrophotometric and potentiometric titrations. The overall stability constants of the quinolobactin-FeIII complexes was found to be log beta111 = 18.60+/-0.10, log beta121 = 32.60+/-0.20, log beta120 = 28.20+/-0.25 resulting in a pFeIII value of 18.2 at pH 7.4. The UV-visible spectral parameters of the [FeL2] are in agreement with a complex containing two ligands coordinated to one Fe3+ cation through the oxygen and nitrogen quinoline atoms.
du Dhardemare
A Moulinet
AM
Laboratoire de Chimie Biomimétique, LEDSS, UMR CNRS 5616, Université J Fourier, Grenoble cedex 9, France. amaury.d-hardemare@ujf-grenoble.fr
Serratrice
G
G
Pierre
J L
JL
D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry / Q000378:metabolism; D007502:Iron Chelating Agents / Q000378:metabolism / Q000494:pharmacology; D033862:Iron-Binding Proteins / Q000737:chemistry; D007700:Kinetics; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D009584:Nitrogen / Q000737:chemistry; D009842:Oligopeptides / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D011199:Potentiometry; D011522:Protons; D011551:Pseudomonas fluorescens / Q000378:metabolism; D011804:Quinolines / Q000737:chemistry / Q000494:pharmacology*; D017262:Siderophores / Q000737:chemistry; D013053:Spectrophotometry; D014466:Ultraviolet Rays
D007502:Iron Chelating Agents; D033862:Iron-Binding Proteins; D008024:Ligands; D009842:Oligopeptides; D011522:Protons; D011804:Quinolines; D017262:Siderophores; C404845:quinolobactin; C042453:pyoverdin; D007501:Iron; D009584:Nitrogen; D010100:Oxygen