Involvement of colchicine binding site of tubulin in the polymerisation process

Role of lysine residues in the colchicine binding site and in the assembly-disassembly process was examined. It was observed that at 4 degrees C (pH 7.5-8, 8 +/- 1) lysine residues and the N-terminal methionine residue of tubulin were all buried within the molecule. Evidence indicates that epsilon-amino groups of lysine residues of tubulin are shared by both the colchicine binding site and the polymerisation process.