The Cytosol-membrane interface of normal and sickle erythrocytes: Effect of hemoglobin deoxygenation and sickling.

Sickle cell anemia is a molecular disease whose medical manifestation results from the polymerization, under low oxygen conditions, of mutant hemoglobin inside the red blood cell. It has been recognized for some time that this process involves the cell's membrane, in possibly promoting the initiation of sickling and in the sickling causing permanent damage to the membrane ("irreversibly sickled cells"). This work explores the relationship between the cytosol hemoglobin and the membrane by employing resonance energy transfer (RET) from fluorescent probes embedded in the membrane to the hemes in the cytoplasm. Since the range of RET for these probes is less than 100 angstrom, RET provides a unique tool for measuring the cytoplasm's boundary layer.