title: Evidence for a common siderophore transport system but different siderophore receptors in Neurospora crassa.
abstract: Uptake and competition experiments were performed with Neurospora crassa and Penicillium parvum by using 14C-labeled coprogen and 55Fe-labeled ferrichrome-type siderophores. Several siderophores of the ferrichrome family, such as ferrichrome, ferricrocin, ferrichrysin, and tetraglycyl-ferrichrome as well as the semisynthetic ferricrocin derivatives O-(phenyl-carbamoyl)-ferricrocin and O-(sulfanilyl-carbamoyl)-ferricrocin were taken up by N. crassa. The ferrichrome-type siderophores used vary in the structure of the peptide backbone but possess a common lambda-cis configuration about the iron center and three identical ornithyl-delta-N-acetyl groups as surrounding residues. This suggests that these ferrichrome-type siderophores are recognized by a common ferrichrome receptor. We also concluded that the ferrichrome receptor is lambda-cis specific from the inability to take up the synthetic enantiomers, enantio-ferrichrome and enantio-ferricrocin, possessing a delta-cis configuration about the iron center. On the other hand, we found that coprogen, possessing a delta-absolute configuration and two trans-anhydromevalonic acid residues around the metal center, was also taken up by N. crassa and was competitively inhibited by the ferrichrome-type siderophores. We therefore propose the existence of a common siderophore transport system but the presence of different siderophore receptors in N. crassa. In addition, ferrirubin, which is very slowly transported by N. crassa, inhibited both coprogen and ferrichrome-type siderophore transport. Contrary to the findings with N. crassa, transport experiments with P. parvum revealed the presence of a ferrichrome receptor but the absence of a coprogen receptor; coprogen was neither transported nor did it inhibit the ferrichrome transport.
authors.forename: H
authors.initials: H
authors.lastname: Huschka
authors.forename: H U
authors.initials: HU
authors.lastname: Naegeli
authors.forename: H
authors.initials: H
authors.lastname: Leuenberger-Ryf
authors.forename: W
authors.initials: W
authors.lastname: Keller-Schierlein
authors.forename: G
authors.initials: G
authors.lastname: Winkelmann
mesh_terms: D001425:Bacterial Outer Membrane Proteins; D001692:Biological Transport; D007476:Ionophores / Q000378:metabolism; D007502:Iron Chelating Agents / Q000378:metabolism*; D007700:Kinetics; D009491:Neurospora / Q000378:metabolism*; D009492:Neurospora crassa / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017262:Siderophores
chemical_list: D001425:Bacterial Outer Membrane Proteins; D007476:Ionophores; D007502:Iron Chelating Agents; D011956:Receptors, Cell Surface; D017262:Siderophores; C035902:siderophore receptors