High‐Level Gene Expression for Recombinant Penicillin Acylase Production Using the <i>araB</i> Promoter System in <i>Escherichia coli</i>
Bibliographic record
Abstract
The pac gene encoding penicillin acylase (PAC) was overexpressed under the regulation of the araB promoter (ParaB, also known as PBAD) in Escherichia coli (E. coli). The current ParaB expression system exhibited minimum leaking pac expression in the absence of arabinose as well as fast and high-level pac expression upon induction with arabinose in a wide concentration range. The production of PAC was limited by the accumulation of PAC precursors (i.e., proPAC in both soluble and insoluble forms) and various negative cellular responses, such as growth arrest and cell lysis. The culture performance could be improved by degP coexpression and the individual contribution of DegP protease and chaperone activities to the enhancement on the production of PAC was characterized. The study highlights the importance of identifying the step(s) limiting high-level gene expression and subsequent design and construction of the host/vector system for enhancing recombinant protein production in E. coli.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".