Theoretical analysis of amino acid sequence of human dystrophin.

Human muscular dystrophy, the fatal disease, is caused by the genetic abnormality of dystrophin. The question whether dystrophin is an intrinsic membrane protein or not was investigated by calculating the average value and the long periodicity of hydrophobicity of amino acid sequence. The periodicity was estimated by a maximum entropy method of Fourier transformation. The results indicated that a fragment from 3101-st to 3200-th residues of dystrophin contains several transmembrane helices. The hydropathy plot of this region strongly suggests four transmembrane helices, indicating that both ends, N-and C-termini, are located in the cytoplasmic sides with firm anchoring into membrane by these helices.