Which of the subunits, when activated, associates with adenylyl cyclase (adenylate cyclase) and enables it to assume a more catalytically active conformation?

aspartate, lysine, arginine and asparagine residues

Explanation:

The activity of adenylyl cyclase (adenylate cyclase) is regulated by the conformation changes on the protein sub-units of the quartenary structure of the enzyme. These consist the amino acid groups that make the structure. For  instance, the amino acid aspartate, lysine, arginine and asparagine all experience change of some sort. The residues stabilize the transition state of the enzyme. The proteins, while the enzyme carries the catalytic activity, mat become slightly mutated.