Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
泉 雄大
no journal, ,
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. However, the dynamics of histones during DNA damage repair processes is not explained completely. In this work, we confirmed whether the structural alterations of histone H2A and H2B (H2A-H2B) are induced by DNA damage responses using vacuum ultraviolet circular dichroism (VUV-CD) spectroscopy. The VUV-CD spectra showed that 
-helix content of H2A-H2B extracted from X-irradiated human cells relatively increased comparing to that from unirradiated cells (38.3 
46.5%). Since X-ray damage to H2A-H2B itself induces decrement of -helix structures, we concluded that the structural alterations were induced as a results of DNA damage responses, such as DNA damage repair processes.
泉 雄大; 藤井 健太郎; 山本 悟史*; 松尾 光一*; 横谷 明徳
no journal, ,
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 H2A and H2B (H2A-H2B) induced by X-ray irradiation to human cells. In this work, we investigated structural alterations of H3 and H4 (H3-H4) extracted from X-irradiated cells using vacuum ultraviolet circular dichroism (VUV-CD) spectroscopy. The VUV-CD spectral shape of H3-H4 extracted from X-irradiated cells was different from that from unirradiated cells. Analyzing the CD spectra, we found that -helix structure component of H3-H4 relatively decreased by X-irradiation to cells. This is an opposite of structural change observed in H2A-H2B. The mechanism of histone structural alterations in response to X-ray irradiation has not been identified yet, but a possible mechanism could be via post-translational modifications which are known to occur in histones during DNA damage responses. Cyclopedic VUV-CD spectroscopy of specific modified-histones to understand the alteration mechanism and its contribution to DNA repair processes is warranted for future studies.