Welcome to QSalignWeb
This is a server for QSalign, a method that uses full Quaternary Structure (QS) superposition to infer the physiological relevance of a QS. This approach leverages the redundancy found in the Protein Data Bank (PDB), where homologous structures are often available. It is a two-step procedure: first, structural superpositions are carried between a Query and representative structures from the PDB to find homologs (global TM-score > 0.65). Second, based on the structural conservation relationships that were detected, the web-server predicts whether the QS of the query is physiological or whether it is likely to represent crystal contacts.

Typical QSalign output are available 1oab_1 1i24_1

If you wish to download bulk predictions, we recommend visiting http://www.QSbio.org where you will find pre-computed annotations for ~63,000 homo-olgomeric and ~10,000 hetero-oligomeric structures of the PDB along with manual annotations from PIQSI