Now, at the center of these individual subunits are the heme groups. And at the center of the actual hemoglobin molecule is this pocket of space. And in the pocket of space, we have three amino acids coming from the beta one subunit, we have histidine 141, Lysine 82, and HistoGene two. And we also have three amino acids coming from the beta two, also the HistoGene two, the Lysine 82 and the histadine 143. And each one of these amino acids contain side chain groups, which contain a positive charge. And so together, these six amino acids create a relatively large positive charge at the center of that hemoglobin.