Q. No 31. Binding of an antibody to its cognate antigen does NOT involve
Covalent bonds
Antibody-antigen binding relies on non-covalent interactions for specificity and reversibility. Covalent bonds do not participate in this process.
Option Analysis
Antibody binding to cognate antigen involves multiple weak non-covalent forces in the complementarity-determining regions (CDRs). These ensure high affinity through cumulative effects.
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(A) Electrostatic forces: These occur between oppositely charged groups on antigen and antibody, contributing to initial recognition and stability.
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(C) Van der Waals forces: Weak attractions from transient dipoles act over short distances, stabilizing close surface complementarity.
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(D) Hydrogen bonds: Form between polar atoms like oxygen and nitrogen, providing specificity in epitope-paratope fitting.
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(B) Covalent bonds: Absent in natural binding; such bonds would make interactions irreversible, unlike the dynamic immune response.
Antibody-cognate antigen binding is a cornerstone of immunology, crucial for CSIR NET Life Sciences aspirants. This process exemplifies non-covalent interactions driving immune specificity without covalent bonds.
Key Interactions in Binding
The antigen-binding site on antibodies forms via hypervariable loops contacting epitopes through:
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Electrostatic forces between charged residues.
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Hydrogen bonds linking polar groups.
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Van der Waals forces for surface complementarity.
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Hydrophobic effects excluding water.
Covalent bonds are excluded to allow reversible, high-avidity binding.
CSIR NET Relevance
Questions on antibody-cognate antigen binding test understanding of non-covalent forces versus covalent ones. Correct answer: Covalent bonds do not participate, enabling rapid on-off kinetics for immune surveillance.
