Table 3.
Sequence variations in the drug binding sites of beta tubulin isotypes
| Binding sites | Isotypes | Inter-isotypic mutations |
|---|---|---|
| Paclitaxel binding site | III | Ser275-Ala |
| VI | Val23-Met, Ser25-Gly, Asp26-Glu, Ser275-Ala, Arg276-Gln | |
| Colchicine binding site | III | Cys239-Ser, Ala315-Thr, Thr351-Val |
| V | Cys239-Ser, Ala315-Thr, Thr351-Val | |
| VI | Val236-Ile, Cys239-Ser, Ala315-Thr, Thr351-Val | |
| Vinblastine binding site | III | Thr218-Ala |
Substitutions observed between βI and the other human β-tubulin isotypes in paclitaxel, colchicine, and vinblastine binding sites