Ligand-specific opening of a gated-porin channel in the outer membrane of living bacteria. Science 1997 May 23;276(5316):1261-4
Date
05/23/1997Pubmed ID
9157886DOI
10.1126/science.276.5316.1261Scopus ID
2-s2.0-0030926805 (requires institutional sign-in at Scopus site) 98 CitationsAbstract
Ligand-gated membrane channels selectively facilitate the entry of iron into prokaryotic cells. The essential role of iron in metabolism makes its acquisition a determinant of bacterial pathogenesis and a target for therapeutic strategies. In Gram-negative bacteria, TonB-dependent outer membrane proteins form energized, gated pores that bind iron chelates (siderophores) and internalize them. The time-resolved operation of the Escherichia coli ferric enterobactin receptor FepA was observed in vivo with electron spin resonance spectroscopy by monitoring the mobility of covalently bound nitroxide spin labels. A ligand-binding surface loop of FepA, which normally closes its transmembrane channel, exhibited energy-dependent structural changes during iron and toxin (colicin) transport. These changes were not merely associated with ligand binding, but occurred during ligand uptake through the outer membrane bilayer. The results demonstrate by a physical method that gated-porin channels open and close during membrane transport in vivo.
Author List
Jiang X, Payne MA, Cao Z, Foster SB, Feix JB, Newton SM, Klebba PEAuthor
Jimmy B. Feix PhD Professor in the Biophysics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Bacterial Outer Membrane ProteinsBacterial Proteins
Biological Transport
Carrier Proteins
Colicins
Cyclic N-Oxides
Cysteine
Electron Spin Resonance Spectroscopy
Enterobactin
Escherichia coli
Escherichia coli Proteins
Ferric Compounds
Indicators and Reagents
Ion Channel Gating
Ligands
Membrane Proteins
Mesylates
Porins
Protein Conformation
Receptors, Cell Surface
Spin Labels
