Structural Determination of the Interaction of H2S and Insulin
Bibliographic record
Abstract
Hydrogen sulfide (H2S) has emerged as an important biological signaling molecule. Its interaction with insulin impacts on glucose and lipid metabolisms. However, the molecular mechanisms underlying the cellular effects of H2S have been unsettled. To obtain direct evidence for H2S-induced post-translational modification of insulin molecule, we structurally characterized insulin following incubation with NaHS, an H2S salt, using X-ray crystallography. Insulin crystals were grown using the hanging drop vapor diffusion method and optimized in MES buffer with PEG MME550 and zinc sulfate. X-ray diffraction data were collected at the Canadian Light Source to resolutions between 2.1–2.2 Å. Six datasets were processed, structures solved and refined (representative structure PDB 9MRA; Rwork/Rfree 0.18/0.23). Structural analysis showed electron density corresponding to a sulfur atom near the amide group of Gln4 in chain B, aligning with prior LC-MS predictions. However, N–S distances ranged from 2.35–3.4 Å across the structures, suggesting the possibility of a transient covalent interaction disrupted by radiation damage during data collection. In addition, one structure exhibited a sulfur atom near Glu residues, suggesting secondary or alternative binding sites. All refined structures were predicted to form hexameric assemblies based on PISA analysis. These results provide structural support to H2S-induced post-translational modification of the insulin molecule.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 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".