Question

One of the mutations that changed the function of the protein Dr. Arnold performed her research on was a mutation that caused a threonine to be replaced by an alanine. Look at the structure of these two amino acids. How did the mutation of this one amino acid affect the function of the protein?

A) Altered binding specificity
B) Enhanced enzymatic activity
C) Increased stability
D) No effect on function

Answer 1

The substitution of threonine with alanine can likely lead to altered binding specificity of the protein, as this change from a polar to a non-polar amino acid can affect the protein's interactions and function.

Step-by-step explanation:

The mutation which led to a threonine being replaced by an alanine in the protein being studied can affect the protein's function significantly. Threonine is a polar amino acid while alanine is non-polar, and this difference can influence how the protein folds, interacts with other molecules, or performs its enzymatic function.

Without evaluating the specific context within the protein, the most likely answer is A) Altered binding specificity, as the change from a polar to a non-polar amino acid side chain can disrupt interactions with substrate or other molecules, potentially altering the protein's ability to bind properly.

This impact on stability, binding, or activity can be compared to the well-documented mutation in sickle cell anemia, where a single nucleotide mutation results in a glutamic acid to valine substitution in hemoglobin, dramatically affecting its structure and function.