Movie S6.

Polymerization of 7 μM PfAct1 in the presence of 2.5 mM BeF₂. Beryllium fluoride suppresses fast depolymerization from the pointed end. Many filaments have a short bright oligomer at the pointed end. Filaments were visualized with 0.5 μM actin-chromobody (ChromoTek). Frame rate, 120x real time; bar, 5 μm.