In order to understand and regulate the functions of biological macromolecular systems such as protein, DNA, and RNA, we must elucidate the atomistic and dynamical mechanisms that are responsible for their biological functions, at the level of the 3D structures and electronic structures. For this purpose, theoretical and computational techniques have been more and more critical. So, our researches are aimed at developing novel computational/theoretical techniques and applying such state-of-the-art methodologies to important biological systems such as transcriptional network system, translational system, signal transduction cascade system, and bioenergetics.