Bottom-Up Mesoscale Model of Microtubule

Microtubules (MTs) are fundamental structural elements in the cytoskeleton of all eukaryotic cells. The MTs are hollow cylinder-shaped biopolymers with inner and outer diameter of about 18 and 30 nm respectively and length ranging from 1 to 10 μm. They are constituted by αβ-tubulins arranged in protofilaments with head-to-tail motif. The protofilaments bind together laterally along the MT’s long axis with a slight shift generating a spiral with a pitch of 2, 3 or 4 monomers’ length [1]. The building-block of the MT, αβ-tubulin, is a hetero-dimer made of two globular monomers, α- and β-tubulin. α- and β-tubulin monomers consists of about 450 residues and shows a high degree of similarity from the primary to the tertiary structure level. However, one important difference is that the α-monomer binds a GTP molecule while the β-monomer binds a GDP molecule [2].