Calculate the percent change in the primary sequence represented by a single-residue substitution for a protein 300 amino acids long. Show your work.

• A. Approximately 0.33% change
• B. Approximately 0.0033% change as changes are scaled by the square of the total residues for tertiary structure considerations
• C. Exactly 1% change because a single substitution is always treated as one percent regardless of length
• D. Approximately 3.33% change because percent is calculated per ten residues for proteins of this size

Answer: (A)