Modular organization and conformational variability of the yeast SAGA complex (LB187)
Bibliographic record
Abstract
Spt‐Ada‐Gcn5‐Acetyltransferase (SAGA) is a conserved histone acetyltransferase complex that regulates transcription through acetylation and deubiquitination of nucleosomal histones. The 19 subunits constituting SAGA are thought to organize into four modules. To further elucidate the relationship between these modules, we developed an improved purification method that enhances the stability of SAGA and used single‐particle electron microscopy to examine the overall architecture and organization of this complex. Our two‐ and three‐dimensional analyses revealed that SAGA is flexible and adopts three major conformations involving large‐scale rearrangements of its subunits. Subunit deletion and labeling showed that the acetyltransferase module is located in the most mobile region of the complex, and that the loss of the deubiquitination module reduces SAGA’s ability to adopt one specific conformation. These results lead to a working model in which the different modules of SAGA coordinate to mediate structural remodeling, which in turn accommodates binding of various substrates and transcriptional activators.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".