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AAT Bioquest

How does the structure of the variable domain of an antibody allow it to bind with high affinity to its epitope?

Posted April 24, 2020


Answer

The variable domains of an antibody are found on the Fab, or antigen binding fragment region of the antibody, which consists of heavy and light chains. Each variable domain contains six hypervariable loops in both the heavy chain and light chain; these six hypervariable loops are also known as complementary determining regions (CDRs). Dimerization of the variable domains on the light and heavy chains and folding of the CDRs creates a paratope, or antibody binding site. The hypervariability of the loops plays an integral part in allowing the paratope to be highly specific for an epitope.

Additional resources

Sela-Culang, I., Kunik, V., & Ofran, Y. (2013). The structural basis of antibody-antigen recognition. Frontiers in immunology, 4, 302. doi:10.3389/fimmu.2013.00302