framework region meaning
That region of the immunoglobulin (antibody) molecule that varies in its amino acid sequence and composition,confers the antigenic specificity,and is thought to comprise the binding site for the antigen. It is located at the N-terminus of the Fab fragment of the immunoglobulin. It includes hypervariable regions (COMPLEMENTARITY DETERMINING REGIONS) and framework regions.
- The framework region makes up about 85 % of the variable region.
- They also accumulate many mutations in the framework region that increase breadth and potency.
- The rest of the V region between the hypervariable regions are called framework regions.
- The framework region is made up of four amino acid segments between the three CDRs of the Fab.
- Residues of the framework region responsible for supporting the binding of the antigen to the antibody can be divided into two categories; residues that are in contact with the antigen and are not in contact with the antigen.