At a high pH, polyglutamate loses its alpha helix structure. What is the primary reason for this change?

• A. The glutamate residues form disulfide bonds.
• B. The glutamate residues become neutral, stabilizing the helix.
• C. The glutamate residues become positively charged, causing attraction.
• D. The glutamate residues become negatively charged, causing repulsion.

Answer: (D)