[Application of fragment molecular orbital (FMO) method to biomacromolecules].

Kitaura et al. (Chem. Phys. Lett. 312, 319-324 (1999)) have proposed an ab initio fragment molecular orbital (FMO) method by which large molecules such as proteins can be easily treated with chemical accuracy. In the ab initio FMO method, a molecule or a molecular cluster is divided into fragments, and the MO calculations on the fragments (monomers) and the fragment pairs (dimers) are performed to obtain the total energy that is expressed as a summation of the fragment energies and inter-fragment interaction energies (IFIEs). In this paper, we provide a brief description of the ab initio FMO method and demonstrate recent applications to the biomacromolecules.