Rotational-echo double-resonance NMR distance measurements for the tubulin-bound paclitaxel conformation

Taxol (paclitaxel, PTX) is an important anticancer drug that owes it unique activity to its ability to bind to tubulin in a stoichiometric ratio and promote its assembly into microtubules. Experimental results from [sup.2.H]{[sup.19.F}] rotational-echo double resonance nuclear magnetic resonance (REDOR NMR) are presented that provide direct confirmation that paclitaxel adopts a T-shaped conformation when it is bound to tubulin.