So what that means is if it comes in close proximity to some type of nonpolar molecule, it will react with that molecule and interact with that molecule via electrostatic interactions. And what happens is if this abnormal beta subunit of one hemoglobin molecule comes in close proximity with the beta subunit of an adjacent deoxy hemoglobin molecule, there are two amino acids, nonpolar amino acids that the valine can interact with. We have valine 88 or a phenylalanine 85. Either one of these non polar amino acids on this beta subunit will interact with this valine and that will form the aggregate. And this will continue its aggregation process and eventually form that long fiber that has a sickle shape and that will distort the biconcape shape and form that sickle shape for those red blood cells. Now, the reason we require a deoxy hemoglobin is because when the hemoglobin molecule is oxygenated, these two amino acids, valine and phenylalamine, disappear into inside that structure of the beta submune.