Spin probe analysis of microtubules structure and formation

[Display omitted] ► Biophysical–biomedical properties of MTs depend on their formation mode. ► Selected spin probes provide information on MT interactions and formation. ► Tubulin and MTs avoid radical quenching due to EGTA in the buffer. ► The kinetics of MTs formation promoted by GTP changes with tubulin concentration. ► At 5mg/mL of tubulin, MTs were formed into 8min. Microtubules (MTs) control cell replication, material transport and motion in eukaryotic cells, but MT role in several pathologies is still unknown. These functions are related to the MT physico-chemical properties and MT formation mode starting from tubulin molecules. This study describes a new method, based on the computer aided analysis of the electron paramagnetic resonance (EPR) spectra of selected spin probes to obtain structural and dynamical information on tubulins and MTs and the kinetics of MTs formation promoted by guanosine-5′-triphosphate (GTP). It was found that tubulin and MTs avoid radical quenching caused by ethylene glycol tetraacetic acid (EGTA). MT formation showed different kinetics as a function of tubulin concentration. At 5mg/mL of tubulin, MTs were formed in 8min. These results are also useful for getting information on MT–drug interactions.