The PDBOBS database at http://pdbobs.sdsc.edu/index.cgi archives versions of PDB entries that have been obsoleted or superseded by more recent versions. These entries are made available for historical purposes, and to allow new versions of software to be tested against the same data sets as earlier versions of the software. The PDBOBS search interface can be used to locate obsolete entries by PDB ID or keyword. A list of obsolete PDB ID's is also available for browsing.

The result of all queries and the links in the browsing pages will graphically display the history of all versions of the PDB entry as well as a textual comparison of the key features of the structure.

A simple view of the sequence and backbone of any obsolete entry can be seen through the QuickPDB applet linked from the PDBOBS home page. This feature also includes a simple search by PDB ID capability. Content statistics and a list of enhancements are also accessible from the PDBOBS home page.

Obsolete PDB entries are also available from the FTP Web site at ftp://ftp.rcsb.org/pub/pdb/data/structures/obsolete/.