This database is a collection of protein-protein transient complexes and domain-domain structures. The present issue of the database contains 1770 entries (as of July 2006) of which 966 are two-chain protein complexes and 804 are one-chain proteins parsed into two domains (domain structures). Detailed description of the database is available here. Each entry consists of the X-ray structure taken from the PDB data bank (in the PDB/ folder), sequence file (in the SEQ/ folder) and the data file (in the INF/ folder) where all relevant information is stored. File names consist of PDB ID and extensions .pdb (X-ray structures), .seq (sequence files or .inf (data files). Current implementation of the database accommodates the following  information for each entry, separately for larger (denoted as chain A^*) and smaller (chain B) components:

• Full sequence;
• Number of residues;
• Number of residues on the interface;
• List of interfacial residues;
• Number of helices and strands;
• Absolute (in Ų) and relative interface areas.

The database is searchable with respect to majority of the above parameters. Additional search is possible with respect to the PDB ID and protein names. Downloads are possible for both individual entries (as plain text files) and for the whole content or search (checked) result list (as one gzipped file). Supplementary download is available for the subset of the database at 40% sequence identity level (the DPPC40 database). Good luck and feel free to sent suggestions or comment by the clicking Send a comment button. Yes, and do not forget to enable Javascript in your browser, otherwise search engine will not work properly!

If usage of the database results to publication please quote the original paper**!

Other relevant resources for protein complexes and domains on Internet:

^* which, in general, may not coincide with the experimental chain designators in the PDB file.
^** P. J. Kundrotas and E. Alexov (2006) Nucleic Acids Research, doi:10.1093/nar/gk1768.