Siderophore-mediated iron uptake systems play a central role in the pathogenesis of infection for many bacterial pathogens. species are not thought to produce siderophores, yet they are able to utilize both ferrichrome and enterochelin as sources of iron. Part of an operon named ceuBCDE, encoding components of a periplasmic binding-protein-dependent transport (PBT) system for the uptake of a ferric siderophore from , was cloned directly into using a plasmid rescue technique. Phenotypic and genetic analyses of this system showed it to comprise two hydrophobic integral membrane proteins, CeuB (35-5 kDa) and CeuC (34-8 kDa), which may form the cytoplasmic membrane permease, an ATP-binding protein, CeuD (28-8 kDa), and a periplasmic substrate-binding protein, CeuE (34-5 kDa). labelling studies using [H]palmitate demonstrated that CeuE, the periplasmic binding protein, is expressed as a lipoprotein in C. , which is unusual for a Gram-negative PBT system. Mutants of C. , defective in components of the transport mechanism, were severely impaired in the ability to utilize enterochelin as an iron source suggesting that this siderophore is a substrate for the transport system. This is the first molecular characterization of a PBT system in species.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error