SIMAP (Similarity Matrix of Proteins) is a public database of pre-calculated protein similarities that plays a key role in many bioinformatics methods. It contains about all currently published protein sequences and is continuously updated. The computational effort for keeping SIMAP up-to-date is constantly increasing. Please help to update SIMAP by calculating protein similarities on your computer. WWW: http://boinc.bio.wzw.tum.de/boincsimap/