Question

Identify the true statements regarding disulfide bridges (disulfide bonds). Include all that apply. a. Disulfide bridges are important to primary and tertiary structure, not quaternary b. Disulfide bridges have a stabilizing effect on proteins c. A disulfide bridge forms between two cysteine residues. d. Disulfide bridges can exist between two amino acid residues on the same chain. e. Disulfide bridges are formed by an irreversible oxidation reaction.

Answer 1

Concepts and reason

A disulphide bond is also termed as disulphide bridge or an S-S bond. The disulphide bond is a covalent bond derived from two thiol groups due to oxidation of sulfhydryl groups. This oxidation process results in the formation of stable protein dimers, polymers, and their complexes in which the sulfide bonds helps in protein folding.

Fundamentals

The process of oxidation of sulfhydryl groups mostly occurs with thiol group of cysteine and the formation of an S-S bond is as follows:

Disulfide bond can occur between only cysteine residues as two thiol functional groups are required to form a disulfide bond.

Disulphide bonds can exist between two amino acid residues on different chains and stabilize the structure of the protein.

Ans:

The correct statements regarding disulfide bridges (disulfide bonds) include:

b. Disulfide bridges have a stabilizing effect on proteins 

c. A disulfide bridge forms between two cysteine residues

d. Disulfide bridges can exist between two amino acid residues on the same chain