Tubulin amino acid sequence and consequences.

The 451 residues of alpha-tubulin from pig brain and the 445 residues of the beta-subunit display 41% sequence identity. Although the primary structure is highly conserved during evolution, several positions in each of the chains are heterogeneous, indicating four alpha-variants and two of the beta-polypeptide. Both C-terminal parts are highly acidic. Small regions can be correlated to sequences of nucleotide binding proteins. Cysteine beta 201 may be involved in the colchicine binding site.