Structure of the full‐length <i>Serratia marcescens</i> acetyltransferase AAC(3)‐Ia in complex with coenzyme A
Bibliographic record
Abstract
Acyl-coenzyme A-dependent N-acetyltransferases (AACs) catalyze the modification of aminoglycosides rendering the bacteria carrying such enzymes resistant to this class of antibiotics. Here we present the crystal structure of AAC(3)-Ia enzyme from Serratia marcescens in complex with coenzyme A determined to 1.8 Å resolution. This enzyme served as an architype for the AAC enzymes targeting the amino group at Position 3 of aminoglycoside main aminocyclitol ring. The structure of this enzyme has been previously determined only in truncated form and was interpreted as distinct from subsequently characterized AACs. The reason for the unusual arrangement of secondary structure elements of AAC(3)-Ia was not further investigated. By determining the full-length structure of AAC(3)-Ia we establish that this enzyme adopts the canonical AAC fold conserved across this family and it does not undergo through significant rearrangement of secondary structure elements upon ligand binding as was proposed previously. In addition, our results suggest that the C-terminal tail in AAC(3)-Ia monomer forms intramolecular hydrogen bonds that contributes to formation of stable dimer, representing the predominant oligomeric state for this enzyme.
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".