The two paralogue <scp> <i>phoN</i> </scp> (phosphinothricin acetyl transferase) genes of <scp> <i>P</i> </scp> <i>seudomonas putida</i> encode functionally different proteins
Bibliographic record
Abstract
Phosphinothricin (PPT) is a non-specific inhibitor of glutamine synthetase that has been employed as herbicide for selection of transgenic plants expressing cognate resistance genes. While the soil bacterium Pseudomonas putida KT2440 has been generally considered PPT-sensitive, inspection of its genome sequence reveals the presence of two highly similar open reading frames (PP_1924 and PP_4846) encoding acetylases with a potential to cause tolerance to the herbicide. To explore this possibility, each of these genes (named phoN1 and phoN2) was separately cloned and their activities examined in vivo and in vitro. Genetic and biochemical evidence indicated that phoN1 encodes a bona fide PPT-acetyl transferase, the expression of which suffices to make P. putida tolerant to high concentrations of the herbicide. In contrast, PhoN2 does not act on PPT but displays instead activity against methionine sulfoximine (MetSox), another glutamine synthetase inhibitor. When the geometry of the substrate-binding site of PhoN1 was grafted with the equivalent residues of the predicted PhoN2 structure, the resulting protein increased significantly MetSox resistance of the expression host concomitantly with the loss of activity on PPT. These observations uncover intricate biochemical and genetic interactions among soil microorganisms and how they can be perturbed by exposure to generic herbicides in soil.
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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) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".