Question

Interactions between side chains of amino acids in a polypeptide chain can be of four forms. Name three. a) Hydrogen bonding, ionic interactions, and van der Waals forces

b) Peptide bonds, disulfide bridges, and hydrophobic interactions
c) Alpha helix, beta sheet, and random coil
d) Primary structure, secondary structure, and tertiary structure

Answer 1

The three key interactions that influence the tertiary structure of proteins are hydrogen bonding, ionic bonding, and disulfide linkages, each of which contributes critically to the overall three-dimensional shape and stability of a protein.

Correct answer is option a.

Step-by-step explanation:

Three interactions between side chains of amino acids in a polypeptide chain that play a crucial role in determining the tertiary structure of proteins are:

• Hydrogen bonding, which occurs between a highly electronegative atom like oxygen or nitrogen and a hydrogen atom attached to another electronegative atom. This interaction is important in both intra- and intermolecular interactions within proteins.
• Ionic bonding, resulting from electrostatic attractions between oppositely charged side chains of amino acids, such as between an aspartic acid carboxylate ion and a lysine ammonium ion.
• Disulfide linkages, which are covalent bonds that form between the sulfur atoms of two cysteine amino acids when their sulfhydryl (SH) groups come in close proximity during protein folding, thereby stabilizing the protein's structure.

These types of interactions are critical for the formation and stabilization of a protein's three-dimensional structure, which in turn determines its function.