```json
{
"ranked_hypotheses": [
{
"rank": 1,
"title": "K280 acetylation creates a transient β-sheet nucleation interface that templates wild-type tau misfolding",
"mechanism": "Acetyl-mimicking mutations at K280 expose a hydrophobic interface that nucleates β-sheet formation in full-length tau, initiating cross-seed templating of wild-type protein.",
"target_gene": "MAPT",
"confidence_score": 0.75,
"novelty_score": 0.65,
"feasibility_score": 0.55,
"impact_score": 0.85,
"composite_score": 0.72,
"testable_prediction": "Cryo-EM of K280-acetylated tau(306-378) will reveal parallel β-sheet density at residues 275-285 not present in unmodified controls.",
"skeptic_concern": "Without atomic-resolution structural data, the proposed β-sheet interface remains a computational prediction; acetylation may instead promote liquid-liquid phase separation rather than fibrillization."
},
{
"rank": 2,
"title": "K280 acetylation selectively disrupts microtubule-binding repeat R2, redirecting tau into a aggregation-competent conformation",
"mechanism": "Neutralization of K280's positive charge disrupts R2 helix capping, exposing the PHF6* motif (275VQIINK280) for β-strand exchange and subsequent oligomerization.",
"target_gene": "MAPT",
"confidence_score": 0.70,
"novelty_score": 0.50,
"feasibility_score": 0.65,
"impact_score": 0.80,
"composite_score": 0.68,
"testable_prediction": "HDX-MS comparing K280Q acetyl-mimic vs K280R charge-neutral mutant will reveal differential H/D exchange patterns in the R2 domain, distinguishing conformational from charge effects.",
"skeptic_concern": "Charge neutralization alone (K280R) may phenocopy acetylation, confounding whether structural rearrangement or electrostatics drives aggregation."
},
{
"rank": 3,
"title": "K280 acetylation promotes cross-talk with K274, creating a dual-site acetylation hub that drives pathological tau conformers",
"mechanism": "K280 acetylation allosterically enables K274 acetylation via local unfolding, generating a doubly-acetylated species with enhanced prion-like spreading capacity.",
"target_gene": "MAPT",
"confidence_score": 0.55,
"novelty_score": 0.80,
"feasibility_score": 0.40,
"impact_score": 0.75,
"composite_score": 0.64,
"testable_prediction": "Double-K-to-Q mutants (K274Q/K280Q) will show >3x faster aggregation kinetics than single mutants in HEK293T biosensor assay, with distinct fibril morphologies by negative-stain EM.",
"skeptic_concern": "Cross-talk hypothesis lacks direct mass spectrometry evidence for simultaneous dual-site acetylation in patient-derived samples."
}
],
"consensus_points": [
"K280 acetylation is associated with early-stage tau pathology and may represent a pathogenic rather than protective modification",
"Atomic-resolution structural evidence is the critical missing data for mechanistically validating any nucleation hypothesis",
"Acetyl-mimicking mutations (K280Q) are imperfect proxies for true acetylation due to differences in side-chain geometry and hydrogen bonding"
],
"dissent_points": [
"Theorist argues β-sheet nucleation interface is primary mechanism; Expert suggests liquid-liquid phase separation may be an alternative or prerequisite pathway that does not require fibril seeding",
"Whether K280 acetylation is cause vs consequence of neurodegeneration remains unresolved—some data support protective compensatory effects"
],
"debate_summary": "The debate centers on whether K280 acetylation nucleates β-sheet formation directly or acts indirectly via charge neutralization and local unfolding. All parties agree structural data is lacking; the Skeptic correctly notes that current evidence cannot distinguish between templated fibrillization and LLPS-mediated condensation models. The Expert's cross-talk hypothesis with K274 is intriguing but speculative without dual-site acetylation validation. Prioritization should favor high-resolution structural studies over further inference from acetyl-mimic mutants."
}
```