Figure 1.

13:3 MT B-lattice. (a) Front view of an entire MT, where sequences of α-tubulin (dark shaded) and β-tubulin (light shaded) repeat along each protofilament in a longitudinal direction. (b and c) Atomistic tubulin-sheets: the standard tubulin-sheet models the standard interaction surfaces found in the MT lattice (b), while the seam tubulin-sheet models, specifically, the interaction in the seam region of the MT wall (c). (Note that, for a better view of the molecular systems, water molecules are not shown, even if present in the simulations.) Each all-atom tubulin-sheet consists of 12 monomers and ∼300,000 atoms. (d) Being representative of the MT wall, tubulin-sheets are curved following the curvature of the MT wall. (e) The αβ-tubulin dimer together with GTP, GDP, and Mg²⁺; this atomistic structure has been used as basic unit to model the tubulin-sheets for MD simulations.