A copper site is required for iron transport by the periplasmic proteins P19 and FetP
Bibliographic record
Abstract
Campylobacter jejuni is a leading cause of food-borne gastrointestinal disease in humans and uropathogenic Escherichia coli is a leading cause of urinary tract infections. Both human pathogens harbour a homologous iron uptake system (termed cjFetM-P19 in C. jejuni and ecFetM-FetP in E. coli). Although these systems are important for growth under iron limitation, the mechanisms by which these systems function during iron transport remain undefined. The copper ions bound to P19 and FetP, the homologous periplasmic proteins, are coordinated in an uncommon penta-dentate manner involving a Met-Glu-His3 motif and exhibit positional plasticity. Here we demonstrate the function of the Met and Glu residues in modulating copper binding and controlling copper positioning through site-directed variants, binding assays, and crystal structures. Growth of C. jejuni strains with these p19 variants is impaired under iron limited conditions as compared to the wild-type strain. Additionally, an acidic residue-rich secondary site is required for binding iron and function in vivo. Finally, western blot analyses demonstrate direct and specific interactions between periplasmic P19 and FetP with the large periplasmic domain of their respective inner membrane transporters cjFetM and ecFetM.
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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 | 0.000 | 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".