Polyglutamic acid is a polypeptide chain made only of glutamic acid residues. It turns out that this polypeptide has a a-helix structure at pH6.0 Suggest a reason for this effect.

As, due to the change in attractions between the side groups. As the pH is increased, the NH₃⁺ ion gets converted to NH₂ and hence the ionic interactions between neighboring molecules is changed. This results in unraveling of the alpha helix and results in a random structure. This is called denaturing of the protein chain.