What is the best explanation for the observed behavior of the E147D variant? The substitution results in:

A repulsive interaction that reduces conformational stability and thus enzymatic activity.

Explanation:

The reason behind this repulsive interaction that leads to reduction of the conformational stability and thus the enzymatic activity is that aspirates has a shorter chain even though both glutamate and aspirate are carboxylic acid. The short chain of aspirate is therefore at a distance from the active site and closer to D348 which leads to repulsive interaction hence reducing conformational stability and enzymatic activity.