The structure of T<sub>6</sub>bovine insulin
Bibliographic record
Abstract
Porcine insulin differs in sequence from bovine insulin at residues A8 (Thr in porcine-->Ala in bovine) and A10 (Ile in porcine-->Val in bovine). The structure of T6 hexameric bovine insulin has been determined to 2.25 A resolution at room temperature and refined to a residual of 0.162. The structure of the independent dimer is nearly identical to the T6 porcine insulin dimer: the mean displacement of all backbone atoms is 0.16 A, with the largest displacements occurring at AlaB30. Each of two independent zinc ions is octahedrally coordinated by three HisB10 side chains and three water molecules. As has been observed in both human and porcine insulin, the GluB13 side chains are directed towards the center of the hexamer, where a short contact of 2.57 A occurs between two independent carboxyl O atoms, again suggesting the presence of a centered hydrogen bond. No significant displacements of backbone atoms or changes in conformation are observed at A8 or A10. Since there are no interhexamer hydrogen-bonded contacts involving A8 in either porcine or bovine insulin, the change in the identity of this residue appears to have little or no effect upon the packing of the hexamers in the unit cell. In contrast, the side chains of the three A10 residues in one trimer make van der Waals contacts with the A10 side chains in a translationally related hexamer. As a consequence of the loss of the C(delta1) atom from the isoleucine residue in porcine insulin to produce valine in bovine insulin, there is a 0.36 A decrease in the distance between independent pairs of C(beta) atoms and a 0.24 A decrease in the c dimension of the unit cell. Thus, the net effect of the change in sequence at A10 is to strengthen the stabilizing hydrophobic interactions between hexamers.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.003 |
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".