Final answer:
The CH1 domain of the heavy chain and the CL domain of the light chain mediate the stability, shape, and immune functions of the antibody, contribute to the determination of the antibody's class or isotype, and engage in interactions with other components of the immune system.
Step-by-step explanation:
The CH1 and CL domains of heavy and light chains play crucial roles in antibody structure and function. Specifically, the CH1 domain of the heavy chain and the CL domain of the light chain are parts of the constant region that contribute to the stability and shape of the antibody. They engage in intrachain disulfide bonds forming loop-shaped structures crucial for the overall conformation.
The CH1 domain of the heavy chain also plays a significant role in determining the antibody's class or isotype, which is essential for directing the appropriate immune response. The constant domains are responsible for the biological functions of the antibodies, such as the activation of complement or binding to Fc receptors, which differ across antibody classes like IgG, IgA, IgM, IgE, and IgD. Additionally, these domains enable antibodies to interact with other components of the immune system and mediate various immune functions.
Both the heavy and light chains are composed of several homologous units of about 110 amino acid residues, which form these functional domains. Each class of antibody utilizes these domains differently, with IgG having three constant domains (CH₁, CH₂, CH₃) in its heavy chains and light chains only having one constant domain (CL).