title: Glutamate-41 of Vibrio harveyi acyl carrier protein is essential for fatty acid synthase but not acyl-ACP synthetase activity.
abstract: Bacterial acyl carrier protein (ACP) is a small, acidic, and highly conserved protein that supplies acyl groups for biosynthesis of a variety of lipid products. Recent modelling studies predict that residues primarily in helix II of Escherichia coli ACP (Glu-41, Ala-45) are involved in its interaction with the condensing enzyme FabH of fatty acid synthase. Using recombinant Vibrio harveyi ACP as a template for site-directed mutagenesis, we have shown that an acidic residue at position 41 is essential for V. harveyi fatty acid synthase (but not acyl-ACP synthetase) activity. In contrast, various replacements of Ala-45 were tolerated by both enzymes. None of the mutations introduced dramatic structural changes based on circular dichroism and native gel electrophoresis. These results confirm that Glu-41 of ACP is a critical residue for fatty acid synthase, but not for all enzymes that utilize ACP as a substrate.
authors.affiliation: Department of Pediatrics, Atlantic Research Centre, Dalhousie University, Rm C-305 Clinical Research Centre, 5849 University Avenue, Nova Scotia, Halifax, Canada B3H 4H7.
authors.forename: Huansheng
authors.initials: H
authors.lastname: Gong
authors.forename: David M
authors.initials: DM
authors.lastname: Byers
mesh_terms: D000213:Acyl Carrier Protein / Q000737:chemistry / Q000378:metabolism*; D002942:Circular Dichroism; D064429:Fatty Acid Synthases / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D014733:Vibrio / Q000378:metabolism*
chemical_list: D000213:Acyl Carrier Protein; D018698:Glutamic Acid; D064429:Fatty Acid Synthases