From the Cover: Ligand-gated diffusion across the bacterial outer membrane.Lepore, B.W., Indic, M., Pham, H., Hearn, E.M., Patel, D.R., van den Berg, B.
(2011) Proc.Natl.Acad.Sci.USA 108: 10121-10126
- PubMed: 21593406
- DOI: 10.1073/pnas.1018532108
- Primary Citation of Related Structures:
- PubMed Abstract:
- Crystal structure of the long-chain fatty acid transporter FadL
van den Berg, B.,Black, P.N.,Clemons Jr., W.M.,Rapoport, T.A.
(2004) Science 304: 1506
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 organism ...
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.
University of Massachusetts Medical School, Program in Molecular Medicine, 373 Plantation Street, Worcester, MA 01605, USA.