Abstract
Vinblastine treatment of microtubule protein or intact microtubules assembled in vitro produced bifilar rings and bifilar helices. Suspentsions of rings and helices were demonstrated to bind [3H]colchicine, a diagnostic property of microtubule protein. Macrotubules are suggested to consist of tightly coiled helices formed by longitudinal compacting of loosely coiled protofilament pair intermediates.
