Iron(III) uptake and release by chrysobactin, a siderophore of the phytophatogenic bacterium Erwinia chrysanthemi.
The plant pathogenic enterobacterium Erwinia chrysanthemi causes important soft-rot disease on a wide range of plants including vegetables and ornamentals of economic importance. It produces a major mono(catecholate) siderophore, chrysobactin (alpha-N-(2,3-dihydroxybenzoyl)-D-lysyl-L-serine). To unravel the role of chrysobactin in the virulence of E. chrysanthemi, its iron(III) coordination properties were thus investigated in aqueous solutions using electrospray ionization mass spectrometric, potentiometric, and spectrophotometric methods. Moreover, kinetic experiments allowed us to determine the uptake and release mechanisms. The formation mechanism of the 1:1 complex reveals a key role of the terminal carboxylic group of chrysobactin in the binding of either FeOH(2+) or Fe2(OH)2(4+). The proton-driven dissociation of the ferric tris-, bis-, and mono(chrysobactin) complexes was also studied. For these three ferric complexes, a single protonation triggers the release of the bound chrysobactin molecule. Interestingly, the dissociation of the last ligand proceeded via the formation of an intermediate for which a salicylate-type mode of bonding was proposed.
Tomisić
Vladislav
V
Laboratoire de Physico-Chimie Bioinorganique, ULP-CNRS (UMR 7177), Institut de Chimie, ECPM, 25 rue Becquerel, 67200 Strasbourg, France.
Blanc
Sylvie
S
Elhabiri
Mourad
M
Expert
Dominique
D
Albrecht-Gary
Anne-Marie
AM
D016974:Dickeya chrysanthemi / Q000378:metabolism*; D004151:Dipeptides / Q000378:metabolism*; D005290:Ferric Compounds / Q000737:chemistry; D007501:Iron / Q000378:metabolism*; D007700:Kinetics; D008024:Ligands; D011199:Potentiometry; D011485:Protein Binding; D017262:Siderophores / Q000378:metabolism*; D013053:Spectrophotometry
D004151:Dipeptides; D005290:Ferric Compounds; D008024:Ligands; D017262:Siderophores; C058543:chrysobactin; D007501:Iron