Question

Light chain and heavy chains in antibody molecule are linked with each other with which of the following force or bond?

• A. Hydrogen bond
• B. Disulphide bond
• C. Van der Waals interactions
• D. Hydrophobic interactions

Hint:

Antibody Chain Linkage: Covalent Interchain Disulfide Bonds ($-S-S-$) join Light chains to Heavy chains ($L-H$) and Heavy chains to Heavy chains ($H-H$).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Immunoglobulin quaternary structure consists of two identical heavy ($H$) and two identical light ($L$) polypeptide chains stabilized by covalent interchain disulfide bridges.

Step 2: Detailed Explanation:
In the basic four-chain ($H_2L_2$) antibody monomer:
- Each light chain is covalently joined to its adjacent heavy chain via an interchain disulfide bond ($-S-S-$ linkage between a conserved cysteine at the C-terminus of the light chain and a cysteine in the $C_H1$ domain of the heavy chain).
- The two heavy chains are interconnected at the flexible hinge region by one or more interchain disulfide bonds.

Step 3: Final Answer:
Thus, light and heavy chains are linked by Disulphide bonds, corresponding to option (B).