Zinc-binding Sites in the N Terminus of Mycoplasma arthritidis-derived Mitogen Permit the Dimer Formation Required for High Affinity Binding to HLA-DR and for T Cell Activation
Bibliographic record
Abstract
Zinc-dependent superantigens can be divided into two subfamilies based on how they use zinc ions for interactions with major histocompatibility complex (MHC) class II molecules. Members of the first subfamily use zinc ions for interactions with histidine 81 on the beta-chain of MHC class II molecules, whereas members of the second subfamily use zinc ions for dimer formation. The zinc-binding motif is located in the C terminus of the molecule in both subfamilies. While our recent studies with Mycoplasma arthritidis-derived mitogen (MAM) have provided the first direct evidence demonstrating the binding to MHC class II molecules in a zinc-dependent manner, it still not known how zinc coordinates the interaction. Data presented here show that the zinc ion is mainly required to induce MAM/MAM dimer formation. Residues in the N terminus of MAM are involved in dimer formation and MHC class II binding, while histidine 14 and aspartic acid 31 of the MAM sequence are the major residues mediating MAM/MAM dimerization. Zinc-induced dimer formation is necessary for MAM binding, MHC class II-induced cell-cell adhesion, and efficient T cell activation. Together these results depict the unique mode of interaction of MAM in comparison with other superantigens.
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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".