Structure of a group III truncated hemoglobin from<i>Camphylobacter jejuni</i>
Bibliographic record
Abstract
Truncated hemoglobins (trHbs) build a protein family loosely related to hemoglobin, showing smaller size and extensive residue substitutions relative to conventional Hbs (< 20% sequence identity).TrHbs, widespread in unicellular organisms and in some plants, bind oxygen, and display diversified functions, including NO-detoxification.The trHb family is divided in three groups, based on amino acid sequences and evolutionary considerations.We have shown in the past that trHbs from group I and II adopt a 2-on-2 alpha-helical sandwich fold, hosting the heme [1].Moreover, a protein matrix tunnel connecting the heme to the protein surface has been identified [2].Here we present the first crystal structure of a group III trHb (from Camphylobacter jejuni, a micro-aerobic prokaryote parasite; data at 2.5 Å resolution, R-gen 21.9%, R-free 26.6%).We show that the trHb fold is modified mostly at the N-terminus, at the C-CD helical region, and in the matrix tunnel, that is closed and filled by core residues in this protein.We present these results at the light of evolution of the trHb and globin folds, and of the two protein families. m11.p02
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".