title: Bacterial long-chain fatty acid transport. Identification of amino acid residues within the outer membrane protein FadL required for activity.
abstract: The outer membrane protein FadL (product of the fadL gene) of Escherichia coli is required for the specific binding and transport of exogenous long-chain fatty acids prior to metabolic utilization. The carboxyl end of FadL has been proposed to play a crucial role by facilitating the transport of long-chain fatty acids. In an attempt to define specific amino acid residues within carboxyl region of FadL essential for activity, a series of deletion and point mutations within the 3' end of the fadL+ gene have been constructed and characterized. These fadL mutants were classified into three categories based on functional properties attributable to the altered FadL proteins: (i) those that had essentially wild-type levels of long-chain fatty acid binding and transport, (ii) those that had wild-type levels of long-chain fatty acid binding but were defective in transport, and (iii) those that were defective for both long-chain fatty acid binding and transport. These findings demonstrate that amino acid residues Phe448, Pro428, Val410, and Ser397 are required for optimal levels of long-chain fatty acid transport and that amino acid residues Pro428 and Val410 are essential for long-chain fatty acid binding.
authors.affiliation: Department of Biochemistry, College of Medicine, University of Tennessee, Memphis 38163.
authors.forename: G B
authors.initials: GB
authors.lastname: Kumar
authors.forename: P N
authors.initials: PN
authors.lastname: Black
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D050612:Fatty Acid Transport Proteins; D005227:Fatty Acids / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D017384:Sequence Deletion; D013604:T-Phages / Q000502:physiology
chemical_list: D000596:Amino Acids; D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D050612:Fatty Acid Transport Proteins; D005227:Fatty Acids; C065691:fadL protein, E coli