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CSA - Catalytic Site Atlas

The Catalytic Site Atlas (CSA) is a database documenting enzyme active sites and catalytic residues in enzymes of 3D structure. We defined a classification of catalytic residues which includes only those residues thought to be directly involved in some aspect of the reaction catalyzed by an enzyme. The CSA contains 2 types of entry: 1. Original hand-annotated entries, derived from the primary literature. References for these entries are given. 2. Homologous entries, found by PSI-BLAST alignment (using an e value cut-off of 0.00005) to one of the original entries. The equivalent residues, which align in sequence to the catalytic residues found in the original entry are documented. Access to the CSA is via PDB code, SWISS-PROT entry or E.C. number. Accessing via PDB code takes you straight to the CSA entry for that PDB, while accessing via SWISS-PROT or E.C. number gives a list of all PDB codes for structures assigned that particular SWISS-PROT identifier or E.C. number. Structures with entries in the CSA are given as hyperlinks. Each CSA entry lists the catalytic residues found in that entry, using PDB residue numbering. Each site is also marked with an evidence tag, which is either Literature reference or PSI-BLAST hit. If the entry is a PSI-BLAST hit you can follow the link to the original entry. You may download the CSA. JESS, an algorithm for constraint-based structural template matching and its application to 3D templates used by the CSA, is available for download.

URL: http://www.ebi.ac.uk/thornton-srv/databases/CSA/

Resource ID: nif-0000-02699     Resource Type: Resource     Version: Latest Version


enzyme, enzyme 3d structure, enzyme catalysis, enzyme structure, catalysis, catalytic site, catalytic residue, gold standard




Catalytic Site Atlas

Additional Resource Types

software resource, database



Parent Organization

Original Submitter


Version Status


Submitted On

12:00am September 20, 2010

Originated From


Changes from Previous Version

First Version

Version 1

Created 5 years ago by Anonymous

The Catalytic Site Atlas: a resource of catalytic sites and residues identified in enzymes using structural data.

  • Porter CT
  • Nucleic Acids Res.
  • 2004 1

The Catalytic Site Atlas (CSA) provides catalytic residue annotation for enzymes in the Protein Data Bank. It is available online at http://www.ebi.ac.uk/thornton-srv/databases/CSA. The database consists of two types of annotated site: an original hand-annotated set containing information extracted from the primary literature, using defined criteria to assign catalytic residues, and an additional homologous set, containing annotations inferred by PSI-BLAST and sequence alignment to one of the original set. The CSA can be queried via Swiss-Prot identifier and EC number, as well as by PDB code. CSA Version 1.0 contains 177 original hand- annotated entries and 2608 homologous entries, and covers approximately 30% of all EC numbers found in PDB. The CSA will be updated on a monthly basis to include homologous sites found in new PDBs, and new hand-annotated enzymes as and when their annotation is completed.