Lecture 1: Antibodies and Molecular Recognition

Question 1

What is the structure of an IgG antibody in terms of oligomeric structure?

Answer 1

Oligomeric: The polypeptide chains of antibodies have multiple domains, and the structure of each domain is an immunoglobulin (Ig) fold.

Question 2

How do antibodies recognize antigens?

Answer 2

Recognition is complementary (highly specific). Involves the formation of noncovalent interactions. Induced fit structural changes occur to enhance specificity and complementary.

Question 3

How are antibody-like molecules useful as drugs?

Answer 3

The variable domains of the antibody have the antigen recognition sites that are designed to bind to the target protein.

Question 4

What is the structure of an IgG antibody in terms of domain structure?

Answer 4

Domain:
1. Two immunoglobulin domains from each chain together form an FAB
fragment.
2. The remaining two immunoglobulin domains from the heavy chains
form an FC fragment

Question 5

What is the structure of an IgG antibody in terms of antigen binding site?

Answer 5

Antigen: The antigen-binding site is formed by the hypervariable loops coming from two Ig domains (VL & VH). Together, the loops generate a
continuous surface complementary to and specific for the antigenic
determinant.