World Library  
Flag as Inappropriate
Email this Article

Complementarity determining region

Article Id: WHEBN0008447410
Reproduction Date:

Title: Complementarity determining region  
Author: World Heritage Encyclopedia
Language: English
Subject: Framework region, Antigen, Antibody, Idiotype, Antibodies
Collection: Amino Acids, Antibodies, Immunology
Publisher: World Heritage Encyclopedia

Complementarity determining region

The "upper" part (Fab region) of an antibody. The complementarity determining regions of the heavy chain are shown in red (PDB 1IGT).

Complementarity determining regions (CDRs) are part of the variable chains in immunoglobulins (antibodies) and T cell receptors, generated by B-cells and T-cells respectively, where these molecules bind to their specific antigen. As the most variable parts of the molecules, CDRs are crucial to the diversity of antigen specificities generated by lymphocytes.


  • Location and structure 1
  • See also 2
  • References 3
  • External links 4

Location and structure

Sketch of an antibody with the variable domains shown in blue, and the CDRs (which are part of the variable domains) in light blue.

In the amino acid sequence of a variable domain of an antigen receptor there are three CDRs (CDR1, CDR2 and CDR3), arranged non-consecutively. Since the antigen receptors are typically composed of two variable domains (on two different polypeptide chains, heavy and light chain), there are six CDRs for each antigen receptor that can collectively come into contact with the antigen. A single antibody molecule has two antigen receptors and therefore contains twelve CDRs. Sixty CDRs can be found on a pentameric IgM molecule.

Within the variable domain, CDR1 and CDR2 are found in the variable (V) region of a polypeptide chain, and CDR3 includes some of V, all of diversity (D, heavy chains only) and joining (J) regions.[1] CDR3 is the most variable.

Since most sequence variation associated with immunoglobulins and T cell receptors are found in the CDRs, these regions are sometimes referred to as hypervariable regions.[2] Among these, CDR3 shows the greatest variability as it is encoded by a recombination of the VJ in the case of a light chain region and VDJ in the case of heavy chain regions.

The tertiary structure of an antibody is important to analyze and design new antibodies. The three-dimensional structures of the non-H3 CDRs of antibodies have been clustered and classified by Chothia et al.[3] and more recently by North et al.[4] Homology modeling is a computational method to build tertiary structures from amino-acid sequences. The so-called H3-rules are empirical rules to build models of CDR3.[5]

See also


  1. ^ William E. Paul (2008). Fundamental Immunology (6th ed.). Lippincott Williams & Wilkins.  
  2. ^ Abbas AK and Lichtman AH (2003). Cellular and Molecular Immunology (5th ed.). Saunders, Philadelphia.  
  3. ^ Al-Lazikani, B.; Lesk, A. M.; Chothia, C. (1997). "Standard conformations for the canonical structures of immunoglobulins". Journal of Molecular Biology 273 (4): 927–948.  
  4. ^ North, B.; Lehmann, A.; Dunbrack Jr, R. L. (2011). "A New Clustering of Antibody CDR Loop Conformations". Journal of Molecular Biology 406 (2): 228–256.  
  5. ^ Shirai, H; Kidera, A; Nakamura, H (1999). "H3-rules: identification of CDR-H3 structures in antibodies". FEBS Letters 455 (1-2): 188–97.  

External links

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.