Fig. 1

Overview of antibody structure. (a) The antibody has a Y-shaped structure, comprising two identical light chains (L) and heavy chains (H). These chains give rise to two Fab segments along with one Fc segment, comprising a total of 12 domains. The Fab segments are those where antigen recognition and binding occur, while the Fc region is primarily responsible for carrying out effector functions. (b) The surface representation of the antibody (PDB code: 1IGT) is depicted in Fig. 1(b). (c) Each Fab's antigen-binding site consists of six hypervariable loops: CDR-L1, CDR-L2, CDR-L3, CDR-H1, CDR-H2, and CDR-H3. These loops are situated on the variable domain pair VL: VH of each Fab, which is also referred to as the variable fragment (Fv)