4.6 Article

On the existence of superradiant excitonic states in microtubules

Journal

NEW JOURNAL OF PHYSICS
Volume 21, Issue -, Pages -

Publisher

IOP PUBLISHING LTD
DOI: 10.1088/1367-2630/aaf839

Keywords

quantum biology; quantum transport in disordered systems; open quantum systems; energy transfer

Funding

  1. PRODEP [511-6/17-8017]
  2. Department of Psychology and Neuroscience
  3. Institute for Neuro-Immune Medicine at Nova Southeastern University (NSU)
  4. NSU President's Faculty Research and Development Grant (PFRDG) program [PFRDG 335426]
  5. National Institute on Minority Health and Health Disparities of the National Institutes of Health [G12MD007597]
  6. US-Italy Fulbright Commission
  7. Whole Genome Science Foundation

Ask authors/readers for more resources

Microtubules are biological protein polymers with critical and diverse functions. Their structures share some similarities with photosynthetic antenna complexes, particularly in the ordered arrangement of photoactive molecules with large transition dipole moments. As the role of photoexcitations in microtubules remains an open question, here we analyze tryptophan molecules, the amino acid building block of microtubules with the largest transition dipole strength. By taking their positions and dipole orientations from realistic models capable of reproducing tubulin experimental spectra, and using a Hamiltonian widely employed in quantum optics to describe light- matter interactions, we show that such molecules arranged in their native microtubule configuration exhibit a superradiant lowest exciton state, which represents an excitation fully extended on the chromophore lattice. We also show that such a superradiant state emerges due to supertransfer coupling between the lowest exciton states of smaller blocks of the microtubule. In the dynamics we find that the spreading of excitation is ballistic in the absence of external sources of disorder and strongly dependent on initial conditions. The velocity of photoexcitation spreading is shown to be enhanced by the supertransfer effect with respect to the velocity one would expect from the strength of the nearest-neighbor coupling between tryptophan molecules in the microtubule. Finally, such structures are shown to have an enhanced robustness to static disorder when compared to geometries that include only short-range interactions. These cooperative effects (superradiance and supertransfer) may induce ultra-efficient photoexcitation absorption and could enhance excitonic energy transfer in microtubules over long distances under physiological conditions.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.6
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available