Biomaterial Database

Characterization of FadL-specific fatty acid binding in Escherichia coli. 1990

P N Black

Department of Biochemistry, College of Medicine, University of Tennessee, Memphis 38163.

The product of the fadL gene (FadL) is a central component of the long-chain fatty acid transport system of Escherichia coli. When fatty acid activation is blocked by a mutation in the structural gene for acyl CoA synthetase (fadD) transport is inhibited allowing a FadL-specific fatty acid binding activity to be measured. This binding activity was 4- to 6-fold greater in the fadL+ fadD strain LS6928 when compared to the delta fadLfadD strain LS6929. With long-chain fatty acids, this binding activity was saturable and it was estimated that there were approx. 35,000 FadL-specific oleic acid binding sites per cell in the fadL+ strain LS6928. The FadL-specific fatty acid binding affinity was highest for oleic acid (18:1) and palmitic acid (16:0) giving apparent KD values of 2.3.10(-7) M and 8.8.10(-7) M, respectively. FadL-specific binding affinity of myristic acid (14:0) was nearly an order of magnitude less and no FadL-specific binding of decanoic acid (10:0) could be measured. Two lines of evidence suggest that FadL-fatty acid binding occurs by a hydrophobic interaction: (1) There was a preference for the long-chain substrates oleic acid and palmitic acid; and (2) oleic acid binding activity was not significantly changed over the pH range 5.0 to 8.0. The FadL-specific binding of oleic acid in the fadL+ strain LS6928 could be blocked by preincubation with antisera raised against purified FadL providing a clear correlation between the activity and identity of FadL. The binding activity associated with FadL was measured in vesicles of the outer membrane following passage over the hydrophobic resin Lipidex 1000. The KD of oleic acid binding attributable to FadL in outer membranes vesicles (6.0.10(-7) M) was in close agreement with that determined in whole cells. Overall, these studies demonstrated that FadL binds long-chain fatty acids with a relatively high affinity prior to their transport across the outer membrane.

UI	MeSH Term	Description	Entries
D007158	Immunologic Techniques	Techniques used to demonstrate or measure an immune response, and to identify or measure antigens using antibodies.	Antibody Dissociation,Immunologic Technic,Immunologic Technics,Immunologic Technique,Immunological Technics,Immunological Techniques,Technic, Immunologic,Technics, Immunologic,Technique, Immunologic,Techniques, Immunologic,Antibody Dissociations,Dissociation, Antibody,Dissociations, Antibody,Immunological Technic,Immunological Technique,Technic, Immunological,Technics, Immunological,Technique, Immunological,Techniques, Immunological
D009829	Oleic Acids	A group of fatty acids that contain 18 carbon atoms and a double bond at the omega 9 carbon.	Octadecenoic Acids,Acids, Octadecenoic,Acids, Oleic
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011991	Receptors, Virus	Specific molecular components of the cell capable of recognizing and interacting with a virus, and which, after binding it, are capable of generating some signal that initiates the chain of events leading to the biological response.	Viral Entry Receptor,Viral Entry Receptors,Virus Attachment Factor,Virus Attachment Factors,Virus Attachment Receptor,Virus Attachment Receptors,Virus Entry Receptor,Virus Entry Receptors,Virus Receptor,Virus Receptors,Attachment Factor, Virus,Attachment Factors, Virus,Attachment Receptor, Virus,Attachment Receptors, Virus,Entry Receptor, Viral,Entry Receptor, Virus,Entry Receptors, Viral,Entry Receptors, Virus,Receptor, Viral Entry,Receptor, Virus,Receptor, Virus Attachment,Receptor, Virus Entry,Receptors, Viral Entry,Receptors, Virus Attachment,Receptors, Virus Entry
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005227	Fatty Acids	Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)	Aliphatic Acid,Esterified Fatty Acid,Fatty Acid,Fatty Acids, Esterified,Fatty Acids, Saturated,Saturated Fatty Acid,Aliphatic Acids,Acid, Aliphatic,Acid, Esterified Fatty,Acid, Saturated Fatty,Esterified Fatty Acids,Fatty Acid, Esterified,Fatty Acid, Saturated,Saturated Fatty Acids
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D001425	Bacterial Outer Membrane Proteins	Proteins isolated from the outer membrane of Gram-negative bacteria.	OMP Proteins,Outer Membrane Proteins, Bacterial,Outer Membrane Lipoproteins, Bacterial
D001692	Biological Transport	The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.	Transport, Biological,Biologic Transport,Transport, Biologic