2. which of the following situations would produce a hill plot with nh < 1.0? explain your reasoning in each case. (a) the protein has multiple subunits, each with a single ligand-binding site. binding of ligand to one site decreases the binding affinity of other sites for the ligand. (b) the protein is a single polypeptide with two ligand-binding sites, site one causes a structural change that decreases affinity for the second ligand. (c) the protein is a single polypeptide with a single ligand-binding site. as purified, the protein preparation is heterogeneous, containing some protein molecules that are partially denatured and thus have a lower binding affinity for the ligand. (d) the protein is multiple subunits and as one ligand binds, the second binds with higher affinity.