Homology modeling of tubulin: influence predictions for microtubule's biophysical properties.

Using comparative modeling, we have generated structural models of 475 alpha and beta tubulins. Using these models, we observed a global, structural similarity between the tubulin isotypes. However, a number of subtle differences in the isotypes physical properties, including net electric charges, solvent accessible surface areas, and electric dipole moments were also apparent. In order to examine the roles that these properties may play in microtubule (MT) assembly and stability, we have created a model to evaluate the dipole-dipole interaction energies of varying MT lattice conformations, using human tubulin isotypes as particularly important examples. We conclude that the dipole moments of each tubulin isotype may influence their functional characteristics within the cell, resulting in differences for MT assembly kinetics and stability.