title: Structure of acyl carrier protein bound to FabI, the FASII enoyl reductase from Escherichia coli.
abstract: Acyl carrier proteins play a central role in metabolism by transporting substrates in a wide variety of pathways including the biosynthesis of fatty acids and polyketides. However, despite their importance, there is a paucity of direct structural information concerning the interaction of ACPs with enzymes in these pathways. Here we report the structure of an acyl-ACP substrate bound to the Escherichia coli fatty acid biosynthesis enoyl reductase enzyme (FabI), based on a combination of x-ray crystallography and molecular dynamics simulation. The structural data are in agreement with kinetic studies on wild-type and mutant FabIs, and reveal that the complex is primarily stabilized by interactions between acidic residues in the ACP helix alpha2 and a patch of basic residues adjacent to the FabI substrate-binding loop. Unexpectedly, the acyl-pantetheine thioester carbonyl is not hydrogen-bonded to Tyr(156), a conserved component of the short chain alcohol dehydrogenase/reductase superfamily active site triad. FabI is a proven target for drug discovery and the present structure provides insight into the molecular determinants that regulate the interaction of ACPs with target proteins.
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY 11794.|Biochemistry and Structural Biology Graduate Program, Stony Brook University, Stony Brook, NY 11794.
authors.forename: Salma
authors.initials: S
authors.lastname: Rafi
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY 11794.
authors.forename: Polina
authors.initials: P
authors.lastname: Novichenok
authors.affiliation: Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794.|Center for Structural Biology, Stony Brook University, Stony Brook, NY 11794.
authors.forename: Subramaniapillai
authors.initials: S
authors.lastname: Kolappan
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY 11794.
authors.forename: Christopher F
authors.initials: CF
authors.lastname: Stratton
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY 11794.
authors.forename: Richa
authors.initials: R
authors.lastname: Rawat
authors.affiliation: Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794.|Center for Structural Biology, Stony Brook University, Stony Brook, NY 11794.|Biochemistry and Structural Biology Graduate Program, Stony Brook University, Stony Brook, NY 11794.
authors.forename: Caroline
authors.initials: C
authors.lastname: Kisker
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY 11794.|Center for Structural Biology, Stony Brook University, Stony Brook, NY 11794.|Biochemistry and Structural Biology Graduate Program, Stony Brook University, Stony Brook, NY 11794.
authors.forename: Carlos
authors.initials: C
authors.lastname: Simmerling
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY 11794.|Biochemistry and Structural Biology Graduate Program, Stony Brook University, Stony Brook, NY 11794.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Tonge
mesh_terms: D000213:Acyl Carrier Protein / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D050753:Enoyl-(Acyl-Carrier-Protein) Reductase (NADH) / Q000737:chemistry* / Q000502:physiology*; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000502:physiology*; D054889:Fatty Acid Synthase, Type II; D006860:Hydrogen Bonding; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D013379:Substrate Specificity; D014443:Tyrosine / Q000737:chemistry
chemical_list: D000213:Acyl Carrier Protein; D029968:Escherichia coli Proteins; D014443:Tyrosine; D050753:Enoyl-(Acyl-Carrier-Protein) Reductase (NADH); C493924:fabI protein, E coli; D054889:Fatty Acid Synthase, Type II