Fig. 4. Schematic representation of the alignment shown in Fig. 3, indicating the location of insertions and deletions in the T. brucei -, - and -tubulin sequence. Red boxes indicate insertions and green chevrons indicate deletions of >5 amino acids; the actual length of each insertion/deletion is indicated. The proposed positions of these insertions/deletions with reference to the secondary structural elements of pig -tubulin shown in Fig. 3 are denoted; for instance, S9-H10 indicates an insertion present on the loop between strand 9 and helix 10. The exact length of each tubulin sequence is shown at the right-hand side of the figure. Also indicated are the limits of the tubulin regions identified as the nucleotide-binding domain, the intermediate domain and the C-terminal domain.