抄録
Non-reparable DNA double strand breaks (dsb) have been attributed to cellular effects induced by ionizing radiation. It is mentioned that radiation damages including dsb are nonspecific in chemical form and in sequence of bases. Recent findings, however, are that (1)5'G of 5'-GG-3' has the lowest ionization potential, indicating an efficient electron donor (2) hole migration exists to 5'G of 5'-GG-3' from neighboring ionized bases, (3)193 nm light induces strand breaks preferentially at G, possibly the hole migration intervening. Little is known the biological reason why the damage or dsb does occur preferentially at G. Structural biology consists of three fields, molecular biology, structural chemistry and computational chemistry. Molecular biology finds out biological function in terms of entity (molecule), and structural chemistry studies the biological function in terms of structure of the molecule using X-ray crystallography and NMR spectroscopy. The computational chemistry studies the biological functions in terms of dynamic properties of the molecule. As an approach of the computational chemistry we exemplify the dynamic properties of the DNA containing a ssb at 5'G 0f 5'-GG-3' using the molecular dynamics simulation. [J Radiat Res 44:380 (2003)]
