Active transportation along microtubules: 600 filament dimers (green/light green) and a nucleating structure (pink) are initially added equally distributed to the reactor (a). These self-assemble into a microtubule (MT) with a 13_3 helix, meaning there are 13 protofilaments and a helicity of three dimers per turn. As a result, a seam forms where α-tubulins bind to β-tubulins laterally (b). Association and dissociation processes constantly happen at the plus end of the MT (c). 50 motor protein dimers (cyan) and 50 cargo particles (purple) are added in the second phase of the simulation. Initially the cargo is equally distributed in the reaction volume (d, top). Finally, a high concentration of cargo particles is created by active transportation at the plus end of the MT (d, bottom). Motor proteins that have already bound to cargoes can bind to the MT as well and start moving to the plus end (e).