PMID:21593406
| Citation |
Lepore, BW, Indic, M, Pham, H, Hearn, EM, Patel, DR and van den Berg, B (2011) Ligand-gated diffusion across the bacterial outer membrane. Proc. Natl. Acad. Sci. U.S.A. 108:10121-6 |
|---|---|
| Abstract |
Ligand-gated channels, in which a substrate transport pathway is formed as a result of the binding of a small-molecule chemical messenger, constitute a diverse class of membrane proteins with important functions in prokaryotic and eukaryotic organisms. Despite their widespread nature, no ligand-gated channels have yet been found within the outer membrane (OM) of Gram-negative bacteria. Here we show, using in vivo transport assays, intrinsic tryptophan fluorescence and X-ray crystallography, that high-affinity (submicromolar) substrate binding to the OM long-chain fatty acid transporter FadL from Escherichia coli causes conformational changes in the N terminus that open up a channel for substrate diffusion. The OM long-chain fatty acid transporter FadL from E. coli is a unique paradigm for OM diffusion-driven transport, in which ligand gating within a β-barrel membrane protein is a prerequisite for channel formation. |
| Links |
PubMed PMC3121852 Online version:10.1073/pnas.1018532108 |
| Keywords |
Bacterial Outer Membrane Proteins/chemistry; Bacterial Outer Membrane Proteins/genetics; Bacterial Outer Membrane Proteins/metabolism; Biological Transport/physiology; Cell Membrane/metabolism; Cell Membrane/ultrastructure; Crystallography, X-Ray; Diffusion; Escherichia coli/cytology; Escherichia coli/metabolism; Escherichia coli Proteins/chemistry; Escherichia coli Proteins/genetics; Escherichia coli Proteins/metabolism; Fatty Acid Transport Proteins/chemistry; Fatty Acid Transport Proteins/genetics; Fatty Acid Transport Proteins/metabolism; Fatty Acids/chemistry; Fatty Acids/metabolism; Ligand-Gated Ion Channels/chemistry; Ligand-Gated Ion Channels/genetics; Ligand-Gated Ion Channels/metabolism; Ligands; Models, Molecular; Molecular Sequence Data; Protein Conformation |
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