title: Conformational analysis of the androgen receptor amino-terminal domain involved in transactivation. Influence of structure-stabilizing solutes and protein-protein interactions.
abstract: The androgen receptor (AR) is a member of the nuclear receptor superfamily. Sequences within the large amino-terminal domain of the receptor have been shown to be important for transactivation and protein-protein interactions; however, little is known about the structure and folding of this region. In the present study we show that a 344-amino acid polypeptide representing the main determinants for transactivation has the propensity to form alpha-helical structure and that mutations which disrupt putative helical regions alter conformation. Folding of the AR was observed in the presence of the helix-stabilizing solvent trifluoroethanol and the natural osmolyte trimethylamine N-oxide (TMAO). TMAO resulted in the movement of two tryptophan residues to a less solvent-exposed environment and the formation of secondary/tertiary structure resistant to protease cleavage. Critically, binding to the RAP74 subunit of the general transcription factor TFIIF resulted in extensive protease resistance, consistent with induced folding of the receptor transactivation domain. These data indicate that this region of the AR is structurally flexible and folds into a stable conformation upon interactions with a component of the general transcription machinery.
authors.affiliation: Department of Molecular and Cell Biology, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Reid
authors.forename: Sharon M
authors.initials: SM
authors.lastname: Kelly
authors.forename: Kate
authors.initials: K
authors.lastname: Watt
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Price
authors.forename: Iain J
authors.initials: IJ
authors.lastname: McEwan
mesh_terms: D002942:Circular Dichroism; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008024:Ligands; D008744:Methylamines / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011944:Receptors, Androgen / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D015533:Transcriptional Activation; D014357:Trypsin / Q000494:pharmacology; D014364:Tryptophan / Q000737:chemistry
chemical_list: D008024:Ligands; D008744:Methylamines; D011944:Receptors, Androgen; D014364:Tryptophan; D005982:Glutathione Transferase; D014357:Trypsin; C005855:trimethyloxamine