Interaction of sickle cell hemoglobin with erythrocyte membranes.
The interactions of hemoglobin S with the erythrocyte membrane were compared with the corresponding interactions of hemoglobin A by measuring in both steady-state and kinetic experiments the quenching of the fluorescence of a probe embedded in erythrocyte membranes. Whereas hemoglobin A could be dissociated from membranes, a fraction of hemoglobin S was irreversibly bound even in the oxy state. Deoxyhemoglobin S interacted much more strongly with erythrocyte membranes than did deoxyhemoglobin A: a portion of the deoxyhemoglobin S was irreversibly bound, and the reversibly bound fraction of hemoglobin S dissociated more slowly than did deoxyhemoglobin A. It is suggested that the binding of deoxyhemoglobin S is a two-step reaction in which the first step involves electrostatic interaction with band III erythrocyte membrane protein and the second step involves a hydrophobic interaction with membrane lipids. The latter reaction reflects the greater hydrophobicity of hemoglobin S. The unique interaction of hemoglobin S with erythrocyte membranes may be important in the formation of irreversibly sickled cells.
D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D005453:Fluorescence; D005986:Glyceraldehyde 3-Phosphate / Q000494:pharmacology; D006441:Hemoglobin A / Q000378:metabolism; D006451:Hemoglobin, Sickle / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007700:Kinetics
D006451:Hemoglobin, Sickle; D006454:Hemoglobins; D005986:Glyceraldehyde 3-Phosphate; D006441:Hemoglobin A