Document Detail


Functional role of fatty acyl-coenzyme A synthetase in the transmembrane movement and activation of exogenous long-chain fatty acids. Amino acid residues within the ATP/AMP signature motif of Escherichia coli FadD are required for enzyme activity and fatty acid transport.
MedLine Citation:
PMID:  12034706     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Fatty acyl-CoA synthetase (FACS, fatty acid:CoA ligase, AMP forming; EC ) plays a central role in intermediary metabolism by catalyzing the formation of fatty acyl-CoA. In Escherichia coli this enzyme, encoded by the fadD gene, is required for the coupled import and activation of exogenous long-chain fatty acids. The E. coli FACS (FadD) contains two sequence elements, which comprise the ATP/AMP signature motif ((213)YTGGTTGVAKGA(224) and (356)GYGLTE(361)) placing it in the superfamily of adenylate-forming enzymes. A series of site-directed mutations were generated in the fadD gene within the ATP/AMP signature motif site to evaluate the role of this conserved region to enzyme function and to fatty acid transport. This approach revealed two major classes of fadD mutants with depressed enzyme activity: 1) those with 25-45% wild type activity (fadD(G216A), fadD(T217A), fadD(G219A), and fadD(K222A)) and 2) those with 10% or less wild-type activity (fadD(Y213A), fadD(T214A), and fadD(E361A)). Using anti-FadD sera, Western blots demonstrated the different mutant forms of FadD that were present and had localization patterns equivalent to the wild type. The defect in the first class was attributed to a reduced catalytic efficiency although several mutant forms also had a reduced affinity for ATP. The mutations resulting in these biochemical phenotypes reduced or essentially eliminated the transport of exogenous long-chain fatty acids. These data support the hypothesis that the FACS FadD functions in the vectorial movement of exogenous fatty acids across the plasma membrane by acting as a metabolic trap, which results in the formation of acyl-CoA esters.
Authors:
James D Weimar; Concetta C DiRusso; Raymond Delio; Paul N Black
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2002-05-28
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  277     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2002 Aug 
Date Detail:
Created Date:  2002-08-12     Completed Date:  2002-09-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  29369-76     Citation Subset:  IM    
Affiliation:
Center for Cardiovascular Sciences, Albany Medical College, Albany, New York 12208.
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MeSH Terms
Descriptor/Qualifier:
Adenosine Monophosphate / metabolism*
Adenosine Triphosphate / metabolism*
Amino Acid Sequence
Amino Acids / metabolism*
Biological Transport
Carbon-Sulfur Ligases / chemistry,  genetics,  metabolism*
Cell Membrane / enzymology
Escherichia coli / enzymology*
Fatty Acids / metabolism*
Molecular Sequence Data
Mutagenesis, Site-Directed
Sequence Homology, Amino Acid
Chemical
Reg. No./Substance:
0/Amino Acids; 0/Fatty Acids; 56-65-5/Adenosine Triphosphate; 61-19-8/Adenosine Monophosphate; EC 6.2.-/Carbon-Sulfur Ligases; EC 6.2.1.20/long-chain-fatty-acid-(acyl-carrier-protein) ligase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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