title: Enhanced oxidative cross-linking of hemoglobin E with spectrin and loss of erythrocyte membrane asymmetry in hemoglobin Ebeta-thalassemia.
abstract: Oxidative stress to the erythrocytes is associated with formation of large molecular complexes of hemoglobin and the skeletal protein, spectrin. In this work, such complexes are formed with hemoglobin mixtures isolated from patients suffering from HbEbeta-thalassemia with elevated levels of the HbE and purified erythroid spectrin in the presence of hydrogen peroxide. The complexes are separated on 4% SDS-PAGE and analyzed by densitometry. The results indicate enhanced formation of complexes with higher amounts of HbE, the most common hemoglobin variant prevalent in Southeast Asia. The binding affinity of spectrin with hemoglobin, in the absence of hydrogen peroxide, was found to increase with hemoglobin mixtures enriched with HbE. The presence of ATP was also found to decrease the overall yield of such complexes. Flow cytometric measurements of phosphatidylserine on the red cell surface also showed a lower degree of membrane asymmetry in HbEbeta-thalassemic patients than in normal subjects. The present work shows enhanced formation of high molecular weight cross-linked complexes of hemoglobin derivatives with erythroid spectrin in HbEbeta-thalassemia.
authors.affiliation: Biophysics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India.
authors.forename: Poppy
authors.initials: P
authors.lastname: Datta
authors.forename: Sumanta
authors.initials: S
authors.lastname: Basu
authors.forename: Sudipa Basu
authors.initials: SB
authors.lastname: Chakravarty
authors.forename: Amit
authors.initials: A
authors.lastname: Chakravarty
authors.forename: Debashis
authors.initials: D
authors.lastname: Banerjee
authors.forename: Sharmila
authors.initials: S
authors.lastname: Chandra
authors.forename: Abhijit
authors.initials: A
authors.lastname: Chakrabarti
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D001665:Binding Sites; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000737:chemistry* / Q000187:drug effects; D005434:Flow Cytometry; D006446:Hemoglobin E / Q000737:chemistry* / Q000187:drug effects / Q000302:isolation & purification; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D011485:Protein Binding; D013049:Spectrin / Q000737:chemistry* / Q000187:drug effects / Q000302:isolation & purification; D013050:Spectrometry, Fluorescence; D017086:beta-Thalassemia / Q000097:blood*
chemical_list: D013049:Spectrin; D000255:Adenosine Triphosphate; D006446:Hemoglobin E; D006861:Hydrogen Peroxide