Question

Which is the most common covalent bond between the side chains of the amino acids that contribute to stabilizing the tertiary structure of a protein?

Answer 1

The disulfide bond, formed between cysteine amino acids, is the most common covalent bond stabilizing the tertiary structure of a protein.

Step-by-step explanation:

The most common covalent bond between the side chains of amino acids that contributes to stabilizing the tertiary structure of a protein is the disulfide bond. Disulfide bonds are formed between two cysteine amino acids within the protein when their side chains come into proximity as the protein folds. The -SH (sulfhydryl) groups on the cysteine side chains undergo an oxidation reaction, leading to the creation of a covalent bond (–S-S–), which provides significant stability to the protein's three-dimensional structure. These covalent bonds supplement other non-covalent interactions such as hydrogen bonding, ionic interactions, and hydrophobic interactions which all play roles in maintaining the tertiary structure.