Complementarity-determining region
part of the variable chains in immunoglobulins (antibodies) and T cell receptors, generated by B-cells and T-cells respectively
Complementarity-determining regions (CDRs) are polypeptide segments of the variable chains in immunoglobulins (antibodies) and T cell receptors, generated by B-cells and T-cells respectively. CDRs are where these molecules bind to their specific antigen and their structure/sequence determines the binding activity of the respective antibody. A set of CDRs constitutes a paratope, or the antigen-binding site. As the most variable parts of the molecules, CDRs are crucial to the diversity of antigen specificities generated by lymphocytes.
Binding affinity
Antibody–antigen interactions are highly specific and those that have high affinity will interact with increased bond strength and trigger downstream immune responses. The strength of the bond between the epitope of the antigen and the paratope of the antibody will determine the affinity of the interaction.
Location and structure
There are three CDRs (CDR1, CDR2 and CDR3), arranged non-consecutively, on the amino acid sequence of a variable domain of an antigen receptor. Three can be found on the Light-chain, named L1 through L3, and three on the Heavy-chain, named H1 through H3. 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 typical monoclonal antibody molecule has two antigen receptors and therefore contains twelve CDRs total.
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This entry incorporates text from “Complementarity-determining region” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.