Question

When a flu virus enters the body, the immune system creates antibodies made of polypeptide chains to fight the virus. The specific shape of the protein allows it to bind to the virus and deactivate it. How does the antibody's primary protein structure create the specific shape to bind to flu viruses?

Answer 1

Answer and explanation:

Antibodies are structures made of four polypeptides, two light (L) chains and two heavy (H) chains that join together and form a molecule shaped like a "Y". This structure is possible thanks to the disulfide bonds that bind light chains and heavy chains together. While the stem of the Y is constant and doesn't change ("constant region"), the tips of the Y, composed of 110-130 amino acids and called "the variable region", vary greatly among the different antibodies and are responsible for the high specificity of these molecules.

This is why we could say that the primary structure of this protein is given by disulfide bridges that twist the antibody and allow it to bind to a protein from the flu virus.