Download MendeleyFrom 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 U S A 108: 10121-10126
- PubMed: 21593406
- DOI: https://doi.org/10.1073/pnas.1018532108
- Primary Citation of Related Structures:
2R89, 2R8A, 3PF1, 3PGR, 3PGS, 3PGU - PubMed 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.
Organizational Affiliation:
University of Massachusetts Medical School, Program in Molecular Medicine, 373 Plantation Street, Worcester, MA 01605, USA.
