The X-Pol theory, first introduced in 1997, is both a fragment-based electronic structure method
and a quantal force field for macromolecular systems.
A New Paradigm for Biomolecular Simulations
|Molecular mechanics dates back to the pioneering studies of steric effects
independently by Hill and by Westheimer, whereas the force field for biomolecular
simulations was established by Lifson in the 1960s. Tremendous progress has been
made in the past fifty years; however, a sobering fact is that the basic
functional form, including polarization terms, has hardly changed. A fundamental
change in force field development is warranted in order to increase the
predictability of computational biology.
In the X-Pol potential, the system is treated explicitly by
electronic structure theory and the wave function (or electron
density) is optimized by self-consistent field (SCF) method.
The internal energy terms and electrostatic potentials
used in classical force fields are replaced and described
explicitly by electronic structure theory. Naturally,
electronic polarization and charge transfer are treated
by the theory. Furthermore, such a method can be
directly used to model chemical reactions, electron transfer, and
electronically excited states.
The X-Pol potential for macromolecular simulations is being developed collaboratively
between the groups of Professor Gao and
Professor Don Truhlar.
The feasibility of the X-Pol potential for modeling
has been recently demonstrated.