Conformational landscape of the yeast SAGA complex as revealed by cryo-EM

Diana Vasyliuk, Joeseph Felt, Ellen D. Zhong, Bonnie Berger, Joseph H. Davis, Calvin K. Yip

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Spt-Ada-Gcn5-Acetyltransferase (SAGA) is a conserved multi-subunit complex that activates RNA polymerase II-mediated transcription by acetylating and deubiquitinating nucleosomal histones and by recruiting TATA box binding protein (TBP) to DNA. The prototypical yeast Saccharomyces cerevisiae SAGA contains 19 subunits that are organized into Tra1, core, histone acetyltransferase, and deubiquitination modules. Recent cryo-electron microscopy studies have generated high-resolution structural information on the Tra1 and core modules of yeast SAGA. However, the two catalytical modules were poorly resolved due to conformational flexibility of the full assembly. Furthermore, the high sample requirement created a formidable barrier to further structural investigations of SAGA. Here, we report a workflow for isolating/stabilizing yeast SAGA and preparing cryo-EM specimens at low protein concentration using a graphene oxide support layer. With this procedure, we were able to determine a cryo-EM reconstruction of yeast SAGA at 3.1 Å resolution and examine its conformational landscape with the neural network-based algorithm cryoDRGN. Our analysis revealed that SAGA adopts a range of conformations with its HAT module and central core in different orientations relative to Tra1.

Original languageEnglish (US)
Article number12306
JournalScientific reports
Volume12
Issue number1
DOIs
StatePublished - Dec 2022
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General

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