beta Tubulin Interactions

Beta-tubulin is one half of the alpha/beta heterodimer from which microtubules are built; the microtubule grows by adding GTP-bound dimers at its end, where a stabilising cap forms, and shrinks when that cap is lost. Drugs grouped here act at beta-tubulin, and binding it prevents dimers from polymerising, so the microtubule-dependent processes of the cell - nutrient uptake, transport, and division - fail. This is the mechanism of the benzimidazole anthelmintics: they bind parasite beta-tubulin with far higher affinity than the host's, which is why the helminth starves while the animal is unharmed.