title: Mapping the deubiquitination module within the SAGA complex.
abstract: The molecular organization of the yeast transcriptional coactivator Spt-Ada-Gcn5 acetyltransferase (SAGA) was analyzed by single-particle electron microscopy. Complete or partial deletion of the Sgf73 subunit disconnects the deubiquitination (DUB) module from SAGA and favors in our conditions the cleavage of the C-terminal ends of the Spt7 subunit and the loss of the Spt8 subunit. The structural comparison of the wild-type SAGA with two deletion mutants positioned the DUB module and enabled the fitting of the available atomic models. The localization of the DUB module close to Gcn5 defines a chromatin-binding interface within SAGA, which could be demonstrated by the binding of nucleosome core particles. The TATA-box binding protein (TBP)-interacting subunit Spt8 was found to be located close to the DUB but in a different domain than Spt3, also known to contact TBP. A flexible protein arm brings both subunits close enough to interact simultaneously with TBP.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Durand
authors.forename: Jacques
authors.initials: J
authors.lastname: Bonnet
authors.forename: Marjorie
authors.initials: M
authors.lastname: Fournier
authors.forename: Virginie
authors.initials: V
authors.lastname: Chavant
authors.forename: Patrick
authors.initials: P
authors.lastname: Schultz
mesh_terms: D001665:Binding Sites; D002843:Chromatin / Q000378:metabolism; D051548:Histone Acetyltransferases / Q000235:genetics*; D008854:Microscopy, Electron / Q000379:methods*; D008958:Models, Molecular; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D015534:Trans-Activators / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry*; D054875:Ubiquitination; D000099224:p300-CBP-Associated Factor
chemical_list: D002843:Chromatin; D051548:Histone Acetyltransferases; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C507785:SAGA complex, S cerevisiae; C093107:SPT7 protein, S cerevisiae; C089445:SPT8 protein, S cerevisiae; C501392:GCN5 protein, S cerevisiae; D000099224:p300-CBP-Associated Factor; C515833:Sgf73 protein, S cerevisiae