Small multidrug resistance protein EmrE phenotypically associates with OmpW, DcrB and YggM for osmotic stress protection by betaine in Escherichia coli
Bibliographic record
Abstract
The small multidrug resistance (SMR) protein EmrE resides in the inner membrane and provides resistance against a wide range of antiseptic quaternary cationic compounds (QCCs) for the Gram-negative bacterium Escherichia coli . We have reported previously that overexpression of the emrE gene results in the reduction of pH and osmotic tolerance, likely through EmrE-mediated biological QCC-based osmoprotectant efflux, indicating a potential physiological role for EmrE beyond providing drug resistance. EmrE is the most studied member of SMR transporter family; however, it is not known how the substrates translocated by EmrE move across the periplasm and through the outer membrane (OM). We have shown that the OM protein OmpW participates in the EmrE-mediated substrate efflux process and provided a hypothesis for the present study that additional OM and periplasmic proteins participate in the translocation process. To test the hypothesis, we conducted alkaline pH-based growth phenotype screens under emrE overexpression conditions. This screen identified 10 additional genes that appear to contribute to the EmrE-coupled osmoprotectant efflux: gspD, hofQ, yccZ, acrA, emrA, emrB, proX, osmF, dcrB and yggM. Further screening of these genes using a hyperosmotic growth phenotype assay in the presence and the absence of the osmoprotectant glycine betaine identified ompW and two periplasmic protein genes, dcrB and yggM, are mechanistically linked to EmrE.
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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 | 0.001 |
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".