Circular dichroism study on structural change of proteins triggering DNA repair

Izumi, Yudai; Yamamoto, Satoshi*; Fujii, Kentaro; Yokoya, Akinari

In a unit chromatin architecture of eukaryotic cells, DNA wraps around histone proteins. It has been gradually recognized that chemical modifications of histones play important roles in DNA repair processes. Kinds of modifications and the functions of modified histones are widely studied, but the conformation of modified histone has not been studied well. In this work, we investigated the secondary structural change of histone H2A/H2B induced by X-ray irradiation to living cells, measuring circular dichroism (CD) spectra. The CD spectra show that -helix structure relatively increased in the X-irradiated cells. The secondary structural change would be induced by chemical modifications of histone H2A/H2B. This structural change may also play important roles in DNA repair processes.