Effects of static magnetic fields on the structure, polymerization and bioelectric of tubulin assemblies.

Due to widespread exposure of human being to various sources of static magnetic fields (SMF), their effect on the spatial and temporal status of structure, arrangement and polymerization of tubulin was studied at molecular level. The intrinsic fluorescence intensity of tubulin was increased by SMF, indicating the repositioning of tryptophan and tyrosine residues. Circular Dichroism (CD) spectroscopy revealed variations in the ratios of alpha helix, beta and random coil structures of tubulin as a result of exposure to SMF at 100, 200 and 300mT. Transmission Electron microscopy (TEM) of microtubules showed breaches and curvatures whose risk of occurrence increased as a function of field strength. Dynamic light scattering revealed an increase in the surface potential of tubulin aggregates exposed to SMF. The rate and extent of polymerization increased by 9.8% and 33.8%, at 100 and 300mT, respectively, but decreased by 36.16% at 200 mT. The conductivity of polymerized tubulin increased in the presence of 100 and 300mT SMF but remained the same as the control at 200mT. The analysis of flexible amino acids along the sequence of tubulin revealed higher SMF susceptibility in the helical electron conduction pathway set through histidines rather than a vertical electron conduction pathway formed by tryptophan residues. The results reveal structural and functional effects of SMF on tubulin assemblies and microtubules that can be considered as a potential means to address the safety issues and for manipulation of bioelectrical characteristics of cytosol, intracellular trafficking and thus living status of cells, remotely.

KEYWORDS: Biophysics; microtubule; molecular flexibility; static magnetic field; tubulin polymerization

PMID: 27794634 DOI: 10.1080/07391102.2016.1254683