Final answer:
Aspartate and glutamate, acidic amino acids, are key components of tertiary and quaternary protein structures due to their ability to form ionic interactions. These amino acids can form bonds called ionic bonds.
Step-by-step explanation:
Aspartate and glutamate, both acidic amino acids, are key components of tertiary and quaternary protein structures due to their ability to form ionic interactions. These interactions are formed between the acidic amino acids (aspartate and glutamate) and basic amino acids (arginine, lysine, or histidine). The bonds formed are called ionic bonds, which result from electrostatic attractions between positively and negatively charged side chains of amino acids.