Question

Which of the following peptides is most likely to form a covalently bonded dimer?

a) A peptide with two cysteine residues at positions close to each other.

b) A peptide with a high content of hydrophobic amino acids.

c) A peptide with a sequence rich in polar amino acids.

d) A peptide with a sequence of alternating charged and uncharged amino acids.

Answer 1

A peptide with two cysteine residues at positions close to each other is most likely to form a covalently bonded dimer due to their ability to create disulfide bonds.

Step-by-step explanation:

The peptide most likely to form a covalently bonded dimer is a peptide with two cysteine residues at positions close to each other. Cysteine residues have the unique ability to form disulfide bonds, which are covalent linkages. For example, in the structure of insulin, two polypeptide chains are joined by a disulfide linkage between cysteine residues, a process that is essential for the proper functioning of this protein. When the thiol side chain of one cysteine (Cys, C) reacts with that of another, a cystine dimer is formed, stabilizing the structure or linking separate peptide chains together.