title: Crystal structure of FadR, a fatty acid-responsive transcription factor with a novel acyl coenzyme A-binding fold.
abstract: FadR is a dimeric acyl coenzyme A (acyl CoA)-binding protein and transcription factor that regulates the expression of genes encoding fatty acid biosynthetic and degrading enzymes in Escherichia coli. Here, the 2.0 A crystal structure of full-length FadR is described, determined using multi-wavelength anomalous dispersion. The structure reveals a dimer and a two-domain fold, with DNA-binding and acyl-CoA-binding sites located in an N-terminal and C-terminal domain, respectively. The N-terminal domain contains a winged helix-turn-helix prokaryotic DNA-binding fold. Comparison with known structures and analysis of mutagenesis data delineated the site of interaction with DNA. The C-terminal domain has a novel fold, consisting of a seven-helical bundle with a crossover topology. Careful analysis of the structure, together with mutational and biophysical data, revealed a putative hydrophobic acyl-CoA-binding site, buried in the core of the seven-helical bundle. This structure aids in understanding FadR function at a molecular level, provides the first structural scaffold for the large GntR family of transcription factors, which are keys in the control of metabolism in bacterial pathogens, and could thus be a possible target for novel chemotherapeutic agents.
authors.affiliation: Wellcome Trust Biocentre, Department of Biochemistry, University of Dundee, Dow Street, Dundee DD1 5EH, UK. dava@davapc1.bioch.dundee.ac.uk
authors.forename: D M
authors.initials: DM
authors.lastname: van Aalten
authors.forename: C C
authors.initials: CC
authors.lastname: DiRusso
authors.forename: J
authors.initials: J
authors.lastname: Knudsen
authors.forename: R K
authors.initials: RK
authors.lastname: Wierenga
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D019281:Dimerization; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D014157:Transcription Factors / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D000214:Acyl Coenzyme A; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C057119:FadR protein, Bacteria; D005227:Fatty Acids; D012097:Repressor Proteins; D014157:Transcription Factors