Microtubules are self-assembling biological helical nanotubes made of the protein tubulin that are essential for cell motility, cell architecture, cell division, molecular signaling, and intracellular trafficking. It has been hypothesized that this hollow molecular nanostructure may support optical transitions in photoexcited tryptophan, tyrosine, or phenylalanine amino acid lattices to function as a light-harvester in similar fashion as photosynthetic units; this ability coupled with its shape is analogous to a quantum wire. In support of this, recent experimental work demonstrates that electronic energy can diffuse across microtubules in a manner that cannot be explained by conventional Förster theory making them effective light harvesters. Here we present theoretical work of energy transfer between amino acids in tubulin via dipole excitations in the presence and absence of a chemical perturbation. Results demonstrate the potential for chemical manipulation of the optical properties of aromatic amino acid lattices in microtubule protein structures.
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