Crystal structure of the long-chain fatty acid transporter FadL.
Publication Type:Journal Article
Source:Science, Volume 304, Issue 5676, p.1506-9 (2004)
Keywords:Amino Acid Sequence, Bacterial Outer Membrane Proteins, Binding Sites, Biological Transport, Crystallization, Crystallography, X-Ray, Escherichia coli, Escherichia coli Proteins, Fatty Acid Transport Proteins, Fatty Acids, Hydrogen Bonding, Hydrophobic and Hydrophilic Interactions, Models, Biological, Models, Molecular, Molecular Sequence Data, Protein Conformation, Protein Structure, Secondary, Protein Structure, Tertiary
<p>The mechanisms by which hydrophobic molecules, such as long-chain fatty acids, enter cells are poorly understood. In Gram-negative bacteria, the lipopolysaccharide layer in the outer membrane is an efficient barrier for fatty acids and aromatic hydrocarbons destined for biodegradation. We report crystal structures of the long-chain fatty acid transporter FadL from Escherichia coli at 2.6 and 2.8 angstrom resolution. FadL forms a 14-stranded beta barrel that is occluded by a central hatch domain. The structures suggest that hydrophobic compounds bind to multiple sites in FadL and use a transport mechanism that involves spontaneous conformational changes in the hatch.</p>