Complete amino acid sequence of alpha-tubulin from porcine brain.

Abstract

The amino acid sequence of .alpha.-tubulin from porcine brain was determined by automated and manual Edman degradation of 8 sets of overlapping peptides. It comprises 450 residues plus a COOH-terminal tyrosine that is present only in 15% of the material. A region of 40 residues at the COOH-terminus is highly acidic, mainly due to 16 glutamyl residues. This high concentration of negative charge suggests a region for binding cations. At least 6 positions, most of them around position 270, are occupied by 2 amino acid residues each. Several of these exchange sites were assigned to specific peptides by analysis of the purified corresponding fragments. Four .alpha.-tubulins in porcine brain are indicated. Although .alpha.-tubulin is unrelated to other proteins, there are regions that can be correlated to sequences of the myosin head, to actin, to tropomyosin and to troponins C and T.