Sickle cell hemoglobin fiber structure altered by α-chain mutation

Abstract

Hybrid hemoglobin molecules prepared with β chains from hemoglobin S (β6 Glu → Val) and α chains from hemoglobin Sealy (α47 Asp → His) form fibers with a novel structure. In contrast to the typical fibers of hemoglobin S with an average diameter of 22 nm and a solid cross section composed of 10 outer filaments surrounding a 4-filament core, the fibers of the α 2(Sealy) β 2(S) hybrid are much larger, with a mean diameter of 32 nm and a unique double-hollow arrangement of filaments. Sealy-S fibers can be described by a model in which the two pairs of filaments most readily lost from fibers of hemoglobin S are missing to form the hollow regions, with an additional sheath of filaments added to form the overall larger structure.