Answer to Question #100986 in Chemistry for Abhishek

Question

Write the structural features of an antibody molecule. Discuss any one mechanism by which antibodies interact with antigens.

Answer 1

An antibody consists of four peptide chains - two heavy and two light peptides joined by disulfide bonds resulting in the formation of a "Y" shaped molecule protein molecule. A "stem" (constant region) of the molecule is formed by two heavy chains, whereas two "branches" consist of variable regions of both heavy and light chains. N-terminal parts of variable regions have specific pockets that directly recognize and bind to antigens. The interaction is mediated by hydrophobic, ionic and hydrogen interactions provided by amino acid side chains and functional groups of the antigen molecule.