Answer to Question #209016 in Zoology for Puja roy

Question

You are an energetic immunology student who has isolated protein X, which you believe is a new isotype of human im munoglobulin.

a. What structural features would protein X have to have in order to be classified as an immunoglobulin? b. You prepare rabbit antisera to whole human IgG, human

K chain, and human y chain. Assuming protein X is, in

fact, a new immunoglobulin isotype, to which of these

antisera would it bind? Why? c. Devise an experimental procedure for preparing an anti serum that is specific for protein X.

Answer 1

Structural features that protein X should have to be classified as an immunoglobulin.

Immunoglobulin is a glycoprotein molecule produced by the plasma cells and it functions as an antibody in response to the presence of an antigen. Immunoglobulin is also known as antibodies and they are normally present in serum and tissue fluid. For the isolated protein X to be considered as an immunoglobulin, it should have the following structural features:

· The protein X should have four linear polypeptide chains arranged in two pairs, heavy and light chains.

· The light chains are supposed to be lighter and shorter with a molecular weight of about 25kDa. The light chains should contain about 240 amino acids. The difference in amino acid sequence leads to the existence of two types of light chains, the lambda and kappa chains.

· The heavy chains are supposed to be long and heavy with a molecular weight of about 55-68kDa. The heavy chains contain about 440 amino acids and the two individual chains are connected covalently by disulfide bonds at 1 and 5.

· Bonding of light and heavy chain should be through single disulfide bond and hydrophobic interactions; the union creates a heterodimer structure that combines with another to create a tetramer structure that appears as “Y” or “I” shape.