Rotational diffusion of the erythrocyte integral membrane protein band 3: effect of hemichrome binding

The rotational diffusion of human erythrocyte band 3 covalently labeled within the integral membrane domain was measured using time-resolved phosphorescence anisotropy. Three rotational correlation times in the range of 16 to 3800 microseconds were observed. This suggests the existence of different aggregate states within the plane of the membrane for band 3. Moreover, it was found that hemichrome binding induces clustering of band 3.