VUV-CD measurements of modified histone proteins

修飾ヒストンタンパクのVUV-CD測定

泉 雄大; 藤井 健太郎; 松尾 光一*; 横谷 明徳

Izumi, Yudai; Fujii, Kentaro; Matsuo, Koichi*; Yokoya, Akinari

DNA wraps around core histone proteins composed of several subunits named as H2A, H2B, H3, and H4 in eukaryotic nuclei. It has been gradually recognized that chemical modifications of histones play important roles in DNA repair processes. Recently, we observed relative increment of -helix structure of histone H2A/H2B induced by X-irradiation to human cells using circular dichroism (CD) spectroscopy. In this work, we investigated the secondary structural change of histone H3/H4 measuring vacuum ultraviolet CD (VUV-CD) spectra. The VUV-CD spectra did not show apparent difference between H3/H4 extracted from X-irradiated cells and that extracted from unirradiated cells. This result suggests that (1) the structure of H3/H4 was not altered although that of H2A/H2B was altered, or (2) opposite structural changes between H3 and H4 occurred, for example, -helix structure of H3 increased, but that of H4 decreased, since CD spectra reflect total amount of each secondary structure.