SMARTFlexDB: a paired apo-holo RNA structure database and analysis platform for RNA conformational flexibility and small-molecule recognition.

SMARTFlexDB links 1187 pocket-level apo–holo RNA pairs across 434 binding pockets from 266 holo structures to 186 apo structures, spanning 150 small molecules and 23 RNA functional classes.

• Why it matters: Existing RNA structural resources often provide only static RNA–ligand snapshots, leaving ligand-bound conformations disconnected from corresponding ligand-free states.
• What they did: The database curates paired apo–holo RNA structures by identifying Protein Data Bank matches with at least 90% sequence identity and coverage and fully conserved binding-pocket nucleotides.
• The result: Each entry integrates apo and holo 3D structures, RNA–ligand atomic interactions, and quantitative global/local conformational-change descriptors, enabling exploration of flexibility and RNA-targeted small-molecule recognition.