title: Generation and characterization of human steroidogenic factor 1 LBD crystals with and without bound cofactor peptide.
abstract: The nuclear receptor Steroidogenic Factor 1 (SF1) plays a critical role in the development of the adrenal gland and gonads, and in sexual differentiation. SF1 performs this pivotal function through the regulation of hormone expression that is essential for organogenesis and endocrine homeostasis. SF1 is a member of a nuclear receptor subclass that contains LRH1 and the Drosophila receptor FTZ-F1. To date, a natural ligand has not been reported for any member of this subfamily. Here we report the crystallization and characterization of the ligand-binding domain (LBD) of human SF1 from two different crystal forms: a binary complex with fortuitous ligand and a ternary complex with the same ligand and a peptide containing a motif of a nuclear receptor cofactor. The structural determination of the binary complex required the use of sulfur SAD phasing, a relatively new technique that uses anomalous diffraction from the endogenous sulfur atoms present in the protein. The structure of the ternary complex was determined by multiple wavelength anomalous diffraction (MAD) using seleno-methionine substituted SF1. Preliminary analysis suggested SF1 contained a fortuitous ligand in the binding pocket. This ligand may account for the relatively high basal activity observed for SF1 in cofactor recruitment and cell-based assays.
authors.affiliation: Department of Pharm. and Cancer Biol., Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Madauss
authors.forename: Dalia
authors.initials: D
authors.lastname: Juzumiene
authors.forename: Greg
authors.initials: G
authors.lastname: Waitt
authors.forename: Jon
authors.initials: J
authors.lastname: Williams
authors.forename: Shawn
authors.initials: S
authors.lastname: Williams
mesh_terms: D003460:Crystallization; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D018398:Homeodomain Proteins; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D051958:Nuclear Receptor Coactivator 2; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D008024:Ligands; C515057:NR5A1 protein, human; D051958:Nuclear Receptor Coactivator 2; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014157:Transcription Factors