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CATH - Protein Structure Classification

Version 2.0 : Released Nov 2000

Dr. Frances M.G. Pearl, Prof. Janet Thornton, Dr. Christine A. Orengo 
Dr. Adrian J. Shepherd, Dr. Andrew Harrison, Dr. David Lee
James Bray, Annabel E. Todd, Ian Sillitoe, Daniel Buchan, Gabby Reeves 



CATH is a novel hierarchical classification of protein domain structures, which clusters proteins at four major levels, Class(C), Architecture(A), Topology(T) and Homologous superfamily (H)

Class, derived from secondary structure content, is assigned for more than 90% of protein structures automatically. Architecture, which describes the gross orientation of secondary structures, independent of connectivities, is currently assigned manually. The topology level clusters structures according to their toplogical connections and numbers of secondary structures. The homologous superfamilies cluster proteins with highly similar structures and functions. The assignments of structures to toplogy families and homologous superfamilies are made by sequence and structure comparisons.
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Orengo, C.A., Michie, A.D., Jones, S., Jones, D.T., Swindells, M.B., and Thornton, J.M. (1997) CATH- A Hierarchic Classification of Protein Domain Structures. Structure. Vol 5. No 8. p.1093-1108.

Pearl, F.M.G, Lee, D., Bray, J.E, Sillitoe, I., Todd, A.E., Harrison, A.P., Thornton, J.M. and Orengo, C.A. (2000) Assigning genomic sequences to CATH Nucleic Acids Research. Vol 28. No 1. 277-282


These WWW pages and the data on which they are based are currently maintained by:- 
  • Dr. Frances Pearl1
  • Mr. James Bray1
  • Ms. Annabel Todd1
  • Mr. Ian Sillitoe1
  • Dr. Andrew Harrison1
  • Prof. Janet Thornton1,6
  • Dr. Christine Orengo1
Previous contributions are acknowledged from:- 
  • Dr. S. Jones1
  • Dr. A.D. Michie2
  • Dr. M.B. Swindells2
  • Dr. G. Hutchinson3
  • Dr. D.T. Jones4
  • Dr. Andrew Martin2
  • Dr. Loredana Lo Conte 8
Thanks for advice and suggestions from:- 
  • Dr. W.R. Taylor5
  • Dr. R. Laskowski6
  • Prof. J.S. Richardson7
1 - University College London
2 - Inpharmatica Ltd.
3 - Reading University
4 - Warwick University
5 - National Institute for Medical Research, Mill Hill
6 - Birkbeck College, London
7 - Duke University, USA
8 - MRC LMB, Cambridge


This project has been developed over many years and has been supported by:-
  • U.K. Biotechnology and Biological Sciences Research Council (BBSRC)
  • U.K. Medical Research Council (Dr. C.A. Orengo) 
  • European Union contract BIOT-CT91-0271 PL 890271 
  • The Wellcome Trust and The Royal Society (Dr. D.T. Jones) 


We acknowledge the contribution of all experimentalists who have deposited their structures in the PDB. We also acknowledge the effort of the staff at the Protein Data Bank for maintaining the data. 

We thank all our colleagues in the BSM unit for their helpful discussions. 

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Last updated 22/12/00