can you give me a correct answer (d) The authors state that protonated histidines were not observed to bind metal ions - binding to neutral histidines is an either/or process. In the absence of metal ions, the two histidines ligands each have pKa's of 6.5. What is the binding energy for these two protons together? -How do they compare with the binding energies for Zn2 and Co+ (calculate these as well)? -How were each of these binding constants determined? -If you determined the histidine pKa's in the presence of a small concentration, say 10 μΜ, of metal ion, which of the two ions would cause the effective pKa to be lowest? (d) The authors state that protonated histidines were not observed to bind metal ions - binding to neutral histidines is an either/or process. In the absence of metal ions, the two histidines ligands each have pKa's of 6.5. What is the binding energy for these two protons together? -How do they compare with the binding energies for Zn2 and Co+ (calculate these as well)? -How were each of these binding constants determined? -If you determined the histidine pKa's in the presence of a small concentration, say 10 μΜ, of metal ion, which of the two ions would cause the effective pKa to be lowest?