Which of the following statements best predicts the effect on the protein's structure if the subunits of the homodimer fail to attach?

(A) The primary structure will change because the order of amino acids will differ.
(B) The secondary structure will differ because hydrogen bonds will occur in different locations and the protein will fold into a different shape.
(C) The tertiary structure will be destroyed because the side chain interactions will not occur and the protein will not fold into a 3-dimensional shape.
(D) The quaternary structure will be destroyed because the different amino acid chains will not join together.

The enzymatic catalysis of a reaction essential in the production of dog saliva is mediated by the protein ARKKKK60491. ARKKKK60491 is a homodimer, with each subunit being 337 amino acids. Figure 1, below, indicates a modular structure of the homodimer. Three positions are indicated on the model. Position A is the active site. Position B is a region known to have a large number of nonpolar residues. Position C is known to have a large number of charged residues.

Transcribed Image Text:

B -------- A C