Electrostatic interactions in three types of metallothioneins aggregates

The electrostatic potential calculations were carried out on three types of metallothioneins. The structure of MT - II in rat liver was obtained direc tly from protein data bank, while other two structures of MT - I and MT - I I in rabbit were constructed by homology modeling. The electrostatic potent ial was calculated by solving the Poisson - Boltzmanne equation using the f inite difference method. In each dimer, two monomers exhibited apparent ele ctrostatic complementarity in buffers of pH 5.6 similar to 8.5. But when pH was increased to 10.6, the electrostatic complementarity would be reduced singnificantly. For all trimers, the electrostatic interactions between the monomer and dimer were unfavorable. Moreover, the electrostatic repulsion would be significantly enhanced when the pH value was changed to 10.6.