Formation of a Gated Channel by a Ligand-Specific Transport Protein in the Bacterial Outer Membrane

The ferric enterobactin receptor (FepA) is a high-affinity ligand-specific transport protein in the outer membrane of Gram-negative bacteria. Deletion of the cell-surface ligand-binding peptides of FepA generated mutant proteins that were incapable of high-affinity uptake but that instead formed non...

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Veröffentlicht in:Science (American Association for the Advancement of Science) 1992-10, Vol.258 (5081), p.471-475
Hauptverfasser: Rutz, Jeanette M., Liu, Jun, Lyons, Jeri Ann, Goranson, Joanne, Armstrong, Sandra K., McIntosh, Mark A., Feix, Jimmy B., Klebba, Phillip E.
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Sprache:eng
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Zusammenfassung:The ferric enterobactin receptor (FepA) is a high-affinity ligand-specific transport protein in the outer membrane of Gram-negative bacteria. Deletion of the cell-surface ligand-binding peptides of FepA generated mutant proteins that were incapable of high-affinity uptake but that instead formed nonspecific, passive channels in the outer membrane. Unlike native FepA, these pores acted independently of the accessory protein TonB, which suggests that FepA is a gated porin and that TonB acts as its gatekeeper by facilitating the entry of ligands into the FepA channel. The sequence homology among TonB-dependent proteins suggests that all ligand-specific outer membrane receptors may function by this gated-porin mechanism.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1411544