The Protein Information Resource (PIR), located at Georgetown University Medical Center, is an integrated public resource of functional annotation of protein data to support genomic/proteomic research and scientific discovery. PIR, directed by Dr. Cathy Wu, maintains the Protein Sequence Database (PSD), an annotated protein database containing over 283,000 sequences covering the entire taxonomic range. PSD grew out of the Atlas of protein sequence and structure edited by Margaret Dayhoff. It also provides access to various databases that reference sequence data from Swiss-Prot, TrEMBL and others.