SCOP: a Structural Classification of Proteins database

The Structural Classification of Proteins (SCOP) database provides a detail ed and comprehensive description of the relationships of known protein stru ctures, The classification is on hierarchical levels: the first two levels, family and superfamily, describe near and distant evolutionary relationshi ps; the third, fold, describes geometrical relationships; The distinction b etween evolutionary relationships and those that arise from the physics and chemistry of proteins:is a feature that is unique to this database so far. The sequences of proteins in SCOP provide the basis of the ASTRAL sequence libraries that can be used as a source of data to calibrate sequence searc h-algorithms and for the generation of statistics on, or selections of, pro tein structures. Links can be made from SCOP to PDB-ISL: a library containi ng sequences homologous to proteins of known structure. Sequences of protei ns of unknown structure can be matched to distantly related proteins of kno wn structure by using pairwise sequence comparison methods to find homologu es in PDB-ISL, The database and its associated-files are freely accessible from a number of WWW sites mirrored from URL http://scop.mrc-lmb. cam.ac.uk /scop/.