title: Crystal structure of the human LRH-1 DBD-DNA complex reveals Ftz-F1 domain positioning is required for receptor activity.
abstract: The DNA-binding and ligand-binding functions of nuclear receptors are localized to independent domains separated by a flexible hinge. The DNA-binding domain (DBD) of the human liver receptor homologue-1 (hLRH-1), which controls genes central to development and metabolic homeostasis, interacts with monomeric DNA response elements and contains an Ftz-F1 motif that is unique to the NR5A nuclear receptor subfamily. Here, we present the 2.2A resolution crystal structure of the hLRH-1 DBD in complex with duplex DNA, and elucidate the sequence-specific DNA contacts essential for the ability of LRH-1 to bind to DNA as a monomer. We show that the unique Ftz-F1 domain folds into a novel helix that packs against the DBD but does not contact DNA. Mutations expected to disrupt the positioning of the Ftz-F1 helix do not eliminate DNA binding but reduce the transcriptional activity of full-length LRH-1 significantly. Moreover, we find that altering the Ftz-F1 helix positioning eliminates the enhancement of LRH-1-mediated transcription by the coactivator GRIP1, an action that is associated primarily with the distantly located ligand-binding domain (LBD). Taken together, these results indicate that subtle structural changes in a nuclear receptor DBD can exert long-range functional effects on the LBD of a receptor, and significantly impact transcriptional regulation.
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Isaac H
authors.initials: IH
authors.lastname: Solomon
authors.forename: Janet M
authors.initials: JM
authors.lastname: Hager
authors.forename: Rachid
authors.initials: R
authors.lastname: Safi
authors.forename: Donald P
authors.initials: DP
authors.lastname: McDonnell
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Redinbo
authors.forename: Eric A
authors.initials: EA
authors.lastname: Ortlund
mesh_terms: D000409:Alanine / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001120:Arginine / Q000737:chemistry; D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005454:Fluorescence Polarization; D051717:Fushi Tarazu Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017930:Genes, Reporter; D018698:Glutamic Acid / Q000378:metabolism; D005998:Glycine / Q000737:chemistry / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006860:Hydrogen Bonding; D008024:Ligands; D008156:Luciferases / Q000378:metabolism; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D020218:Response Elements; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014158:Transcription, Genetic; D014867:Water / Q000737:chemistry
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; C491310:GRIP1 protein, human; D008024:Ligands; C082631:NR5A2 protein, human; D009419:Nerve Tissue Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D014867:Water; D018698:Glutamic Acid; D004247:DNA; D001120:Arginine; D008156:Luciferases; D000409:Alanine; D010100:Oxygen; D005998:Glycine