Viscous effects on polar vibrations in microtubules

Microtubules form a fundamental organization structure in the cytoskeleton of the cell. Electrical polarity and high deformability at low stress are important physical properties of microtubules. Ions from the cytosol are attracted to tubulin heterodimers with electric dipoles and create a charge layer around the surface of the microtubule. Because of the slip boundary conditions in the surface layers of the microtubule and in the adjacent charge layer dissipative effects of viscous damping on vibrations are diminished. At the frequency 10 MHz the relaxation time may be more than 100 times greater than the period of oscillations. Energy supplied by hydrolysis of GTP (guanosine triphosphate) to GDP (guanosine diphosphate) in the beta-tubulins might, therefore, excite vibrations in microtubular structures.