Tubulin lattice neighborhood as in Figure 8 in different contrast. Tryptophans in red, histidines in yellow. If we then show the intra-tubulin tryptophan paths in the lattice format, we see that the tryptophan paths extend vertically along each protofilament. A lattice of 7 tubulin dimers as found in the microtubule lattice. Red lines connect tryptophans, and rectangles show 4 possible winding patterns.
Tryptophans seem oriented vertically whereas histidine locations suggests helical paths.
When added to tryptophan, all possible structural pathways are available, allowing switching and quantum interference effects. Photons may also be involved, as electrons move from a valence band to a conduction band, so each electron jump would involve absorption and emission of a photon. Conclusion An approach to examining possible pathways of electron conduction in microtubules is presented. In a simulation of the tubulin dimer, locations of aromatic amino acids tryptophan, histidine and tyrosine have been identified. These intra-protein electron pathways with in individual dimers were then projected in a microtubule cylindrical lattice, revealing particular helical winding patterns intrinsic to the microtubule lattice structure.