Luoshu Convex-Hull Geometry Predicts Protein Druggability with AUC = 0.846 on 85 DUD-E Targets

Full 85-protein DUD-E benchmark validation of the Luoshu convex-hull druggability framework. Key results: sphericity+area_vol+compact composite AUC=0.846 (95%CI: 0.748-0.929, permutation p<0.001), exceeding SiteMap Dscore (~0.74) by +0.106. Strongest single features: sphericity AUC=0.814, depth_ratio AUC=0.812, chc_max AUC=0.781. New finding: pocket sphericity (how sphere-like the binding cavity is) is as informative as pocket depth for druggability prediction. Druggable pockets are geometrically sphere-like; undruggable PPI surfaces are flat. Method uses only C-alpha coordinates and backbone dihedral angles, O(n^2) time, no ML/MD/ligand data. Transparent reporting: v1 24-protein proof-of-concept AUC=0.957 also reported for comparison. Reference code (druggability_dude.py) included. Extends doi:10.5281/zenodo.20073548