title: Mapping the initiator binding Taf2 subunit in the structure of hydrated yeast TFIID.
abstract: The general transcription factor TFIID is a large multisubunit complex required for the transcription of most protein-encoding genes by RNA polymerase II. Taking advantage of a TFIID preparation partially depleted in the initiator-binding Taf2p subunit, we determined the conformational and biochemical variations of the complex by electron tomography and cryo-electron microscopy of single molecules. Image analysis revealed the extent of conformational flexibility of the complex and the selection of the most homogeneous TFIID subpopulation allowed us to determine an improved structural model at 23 Angstroms resolution. This study also identified two subpopulations of Taf2p-containing and Taf2p-depleted TFIID molecules. By comparing these two TFIID species we could infer the position of Taf2p, which was confirmed by immunolabeling using a subunit-specific antibody. Mapping the position of this crucial subunit in the vicinity of Taf1p and of TBP sheds new light on its role in promoter recognition.
authors.affiliation: Department of Structural Biology and Genomics, Institut de Génétique et de Biologie Moléculaire et Cellulaire CNRS/INSERM/ULP, 67404 Illkirch, France.
authors.forename: Gabor
authors.initials: G
authors.lastname: Papai
authors.forename: Manish K
authors.initials: MK
authors.lastname: Tripathi
authors.forename: Christine
authors.initials: C
authors.lastname: Ruhlmann
authors.forename: Sebastiaan
authors.initials: S
authors.lastname: Werten
authors.forename: Corinne
authors.initials: C
authors.lastname: Crucifix
authors.forename: P Anthony
authors.initials: PA
authors.lastname: Weil
authors.forename: Patrick
authors.initials: P
authors.lastname: Schultz
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D020285:Cryoelectron Microscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship; D035381:TATA-Binding Protein Associated Factors / Q000737:chemistry* / Q000378:metabolism; D035362:Transcription Factor TFIID / Q000737:chemistry* / Q000378:metabolism
chemical_list: D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; C087176:TAF2 protein, S cerevisiae; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID