bookmark RepeatsDB Provides annotated tandem repeat protein structures. RepeatsDB includes high quality annotations for ∼5400 protein structures. RepeatsDB features information on start and end positions for the repeat regions and units for all entries. The extensive growth of repeat unit characterization was possible by applying the ReUPred annotation method over the entire Protein Data Bank. The data quality is guaranteed by a manual validation for more than 60% of the entries. The updated web interface includes a search engine for complex queries and a fully re-designed entry page for a better overview of structural data. It is possible to compare unit positions, together with secondary structure, fold information and Pfam domains.