title: Identification and structural characterization of a CBP/p300-binding domain from the ETS family transcription factor GABP alpha.
abstract: Using NMR spectroscopy, we identified and characterized a previously unrecognized structured domain near the N-terminus (residues 35-121) of the ETS family transcription factor GABP alpha. The monomeric domain folds as a five-stranded beta-sheet crossed by a distorted helix. Although globally resembling ubiquitin, the GABP alpha fragment differs in its secondary structure topology and thus appears to represent a new protein fold that we term the OST (On-SighT) domain. The surface of the GABP alpha OST domain contains two predominant clusters of negatively-charged residues suggestive of electrostatically driven interactions with positively-charged partner proteins. Following a best-candidate approach to identify such a partner, we demonstrated through NMR-monitored titrations and glutathione S-transferase pulldown assays that the OST domain binds to the CH1 and CH3 domains of the co-activator histone acetyltransferase CBP/p300. This provides a direct structural link between GABP and a central component of the transcriptional machinery.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Hyun-Seo
authors.initials: HS
authors.lastname: Kang
authors.forename: Mary L
authors.initials: ML
authors.lastname: Nelson
authors.forename: Cameron D
authors.initials: CD
authors.lastname: Mackereth
authors.forename: Manuela
authors.initials: M
authors.lastname: Schärpf
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Graves
authors.forename: Lawrence P
authors.initials: LP
authors.lastname: McIntosh
mesh_terms: D000818:Animals; D001665:Binding Sites; D051268:GA-Binding Protein Transcription Factor / Q000737:chemistry*; D051379:Mice; D019906:Nuclear Magnetic Resonance, Biomolecular; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D050880:p300-CBP Transcription Factors / Q000737:chemistry*
chemical_list: D051268:GA-Binding Protein Transcription Factor; D050880:p300-CBP Transcription Factors