Ferric iron uptake in Erwinia chrysanthemi mediated by chrysobactin and related catechol-type compounds.
Erwinia chrysanthemi 3937 possesses a saturable, high-affinity transport system for the ferric complex of its native siderophore chrysobactin, [N-alpha-(2,3-dihydroxybenzoyl)-D-lysyl-L-serine]. Uptake of 55Fe-labeled chrysobactin was completely inhibited by respiratory poison or low temperature and was significantly reduced in rich medium. The kinetics of chrysobactin-mediated iron transport were determined to have apparent Km and Vmax values of about 30 nM and of 90 pmol/mg.min, respectively. Isomers of chrysobactin and analogs with progressively shorter side chains mediated ferric iron transport as efficiently as the native siderophore, which indicates that the chrysobactin receptor primarily recognizes the catechol-iron center. Free ligand in excess only moderately reduced the accumulation of 55Fe. Chrysobactin may therefore be regarded as a true siderophore for E. chrysanthemi.
Persmark
M
M
Department of Molecular and Cell Biology, University of California, Berkeley 94720.
Expert
D
D
Neilands
J B
JB
D002396:Catechols / Q000378:metabolism*; D003080:Cold Temperature; D016974:Dickeya chrysanthemi / Q000378:metabolism*; D004151:Dipeptides / Q000378:metabolism*; D005290:Ferric Compounds / Q000378:metabolism*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy
D002396:Catechols; D004151:Dipeptides; D005290:Ferric Compounds; C058543:chrysobactin