Answer:
The types of R-groups
It's shape
Step-by-step explanation:
The structure of an enzyme is strongly related to its function. For example an enzyme structure defines its active site and how that site interacts with the substrate for catalysis of a reaction.
On the other hand, the structure of a protein is highly dependent on the interactions of the R-groups of the amino acids that make up the proteins. The interactions are dependent on the charges of these groups that stabilize protein structures such loops of beta-sheets and alpha-helices. If these charges are affected then the conformation of the protein will also most likely be altered.