Spectrin Jendouba: an alpha II/31 spectrin variant that is associated with elliptocytosis and carries a mutation distant from the dimer self- association site

Spectrin Jendouba (alpha II/31) was found in a Tunisian family. In the heterozygous state, it is associated with asymptomatic elliptocytosis and a minimal defect in spectrin dimer self-association. On partial digestion of spectrin with trypsin, an abnormal cleavage appeared following Lys 788. Peptide and DNA sequencing indicated that the responsible mutation is alpha 791 Asp----Glu (GAC----GAA). As in most alpha-spectrin variants associated with elliptocytosis, the change alters helix 3 of the proposed triple helical model of spectrin structure. Modified helix 3 in repeat alpha 8 is the most distant from the N-terminus of alpha-spectrin in known variants associated with elliptocytosis.