Final answer:
The question addresses the amino acids likely to line binding sites in a protein, which is determined by the chemical nature of their side chains. Amino acids like arginine and histidine, with their positively charged side chains, are commonly involved in such interactions due to their capacity to engage in multiple types of bonds.
Step-by-step explanation:
The question "Sites I and II are most likely lined with the side chains of which amino acids?" pertains to the binding sites of a protein, where specific amino acids with particular side chains interact with other molecules or proteins.
The side chain's nature, whether it is acidic, basic, polar, or nonpolar, determines the kind of interactions it can partake in.
For example, amino acids like valine, methionine, and alanine, with nonpolar side chains, are hydrophobic, while amino acids like serine, threonine, and cysteine are polar and have hydrophilic side chains.
The side chains of arginine and lysine are positively charged, making them basic amino acids.
In general, basic amino acids like arginine (R) and histidine (H) are likely to be found in binding sites because of their ability to form multiple types of interactions.