A point mutation replaces a buried hydrophobic leucine in the core of an enzyme with a charged glutamate. Which chain of structural consequences is most likely, and what functional outcome would you predict?

• A. Only the primary sequence changes; secondary, tertiary, and quaternary structures remain unaffected because side chains buried in cores are always ignored during folding.
• B. Substitution creates a new peptide bond that shortens the polypeptide, thereby increasing activity by making the active site more rigid and accessible.
• C. Local disruption of hydrophobic packing (tertiary level), possible unfolding or altered geometry of the active site (tertiary and possibly quaternary), and likely reduction or loss of enzymatic activity due to destabilization of the native fold.
• D. Improved folding due to increased solubility in the hydrophobic core, leading to enhanced cooperative quaternary assembly and increased activity in most cases.

Answer: (C)