Fiedler Inversion Score (FIS) v3: Calpha-only Spectral Classification of Protein Conformational Transitions -- Expanded Validation n=98
FIS (Fiedler Inversion Score) v3: Expanded validation from n=25 to n=98 protein pairs across 11 functional categories. FIS classifies protein conformational transitions using the cosine angle between Graph Laplacian Fiedler vectors of open and closed states. Parameter-free, computed solely from Calpha coordinates at 8 Angstrom contact cutoff. v3 results (n=98): mean |FIS|=0.7219, four statistical tests all p<0.001 (t-test p=1.35e-8, Wilcoxon p=1.96e-9, permutation p<0.0001, Kruskal-Wallis p=4.24e-5). Three conformational types: Type I domain inversion n=37 (38%), Type II rigidity change n=7 (7%), Type III internal strain n=29 (30%), Mixed n=25 (26%). New finding: 5 additional Type II rigidity proteins beyond EGFR T790M -- FKBP51 (ratio=7.8x, stress/PTSD target), MMP9 (5.6x, anti-MMP antibodies), CRBN (4.3x, lenalidomide/thalidomide molecular glue), Gyrase B (3.4x, fluoroquinolones), ER-alpha (2.2x, fulvestrant). All 7 Type II proteins are targets of approved drugs (100% clinical enrichment). Pipeline open-source (fis_pipeline_n100.py), raw data deposited (FIS_results_n98.csv). Part of Geometric Systems Medicine series. Companion paper: TRIS (DOI: 10.5281/zenodo.20187264). Previous version: FIS v2 (DOI: 10.5281/zenodo.20187256).
Authors
- Yao-Kai Kao
Institutions
- Allen Institute for Brain Science (US)
Publication Details
- Journal
- Zenodo (CERN European Organization for Nuclear Research)
- Published
- 2026-05-14
- DOI
- https://doi.org/10.5281/zenodo.20187552
- Primary Topic
- Protein Structure and Dynamics
- Type
- preprint