iProClass: an integrated, comprehensive and annotated protein classification database

The iProClass database is an integrated resource that provides comprehensiv e family relationships and structural and functional features of proteins, with rich links to various databases. It is extended from ProClass, a prote in family database that integrates PIR superfamilies and PROSITE motifs. Th e iProClass currently consists of more than 200 000 non-redundant PIR and S WISS-PROT proteins organized with more than 28 000 superfamilies, 2600 doma ins, 1300 motifs, 280 posttranslational modification sites and links to mor e than 30 databases of protein families, structures, functions, genes, geno mes, literature and taxonomy, Protein and family summary reports provide ri ch annotations, including membership information with length, taxonomy and keyword statistics, full family relationships, comprehensive enzyme and PDB cross-references and graphical feature display. The database facilitates c lassification-driven annotation for protein sequence databases and complete genomes, and supports structural and functional genomic research. The rPro Class is implemented in Oracle 81 object-relational system and available fo r sequence search and report retrieval at http:// pir.georgetown.edu/iprocr ass/.