Microtubule Electrodynamics Associated with Vibrational Normal Modes

Abstract

Cytoskeleton is a crucial integrating component of cellular functions. Microtubules, as a part of cytoskeleton, are involved in such functions, serving as transportation tracks, signaling substrate and also are fundamental for cellular division. While chemical, mechanical and electrostatic nature of microtubule function in these cellular processes is being researched, current picture of all underlying types of interactions is far from complete.Here, we introduce a new, electrodynamic aspect of microtubule interaction with its molecular partners from combination of the knowledge of atomic-precision electric charge distribution with fast mechanical fluctuation properties of microtubules.First, a microtubule lattice is reconstructed from combined RCSB Protein DataBank 1TUB and 1JFF tubulin structure and interlocking alpha-tubulin loops between adjacent protofilaments are remodeled to obtain physiological conformation. We analyze normal modes of anisotropic elastic network microtubule model obtained by coarse-graining the atomic model and using rotating block approximation. Further, we map the atomic charge distribution upon atomic trajectories of the first 30 normal modes, which lie in GHz spectral region. Approximating the oscillating atomic charges as a Hertzian dipoles, we calculated and visualized electrodynamic field around the microtubule for each normal mode.Based on the results, we suggest that the electrodynamic field around microtubule can provide interactions of different nature than pure electrostatic interactions since the ionic screening is diminished for frequency the electric >10 MHz.Significance of these unique theoretical predictions is planned to be verified in the upcoming experimental studies. Exploitation of microtubule electrodynamic properties could open paths to novel tools for microtubule manipulation with prospects in new therapeutic and diagnostic methods in the future.