The entatic state theorem proposes that enzymes create at the active site an area with its energy closer to that of a unimolecular transition state, rather than that corresponding to a conventional, limiting form of the molecule, thereby constituting an energetically poised domain. Blue copper proteins have a strained structure around the Cu metal that facilitates the CuII/I redox process. Why is a strained structure necessary for rapid electron transfer in the blue copper proteins? (Hint: consider the preferred, thermodynamically stable structures of the two oxidation states of copper).