Effects of Full-Length Phosphorylated Osteopontin and Constituent Acidic Peptides and Amino Acids on Calcite Dissolution
Bibliographic record
Abstract
Mineral dissolution events are part of the life history of many protein-rich biomineralized tissues and structures. To assess under dissolution conditions the specificity of interactions between calcite and phosphate moieties in proteins, the ( 1 0 4 ) surface of calcite single crystals were etched with aqueous solutions containing osteopontin (OPN) protein and examined by atomic force microscopy. Etch pits were compared to those modified by constituent acidic peptides of OPN as well as by single relevant amino acids. Exposure to phosphorylated OPN and phosphorylated acidic serine- and aspartate-rich motif (ASARM) peptides of OPN produced oval or nearly circular etch pits (rather than the rhombic shape when etched in water alone) in the ( 1 0 4 ) calcite surface, with a steep acute [ 0 1 0 ] edge, indicating preferential step-specific binding. A carboxyl-group-rich polyaspartic acid peptide, and the nonphosphorylated ASARM peptide, produced pits predominantly elongated parallel to [ 4 2 1̅ ]. Etch-pit steps parallel to [ 0 1 0 ] were stabilized by the amino acids aspartic acid and phosphoserine, but not by serine. OPN and peptides bearing multiple acidic groups modified pits at concentrations several hundred times lower than did the amino acids alone. Molecule phosphorylation consistently induced step edge rounding, suggesting phosphate-carboxyl cooperative binding to calcium ions at the ( 1 0 4 ) calcite surface and step edges.
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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 | 0.001 |
| 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".