||STRUCTURAL ANALYSIS OF DNA REPAIR PROTEIN (XRCC4) APPLYING CIRCULAR DICHROISM IN AN AQUEOUS SOLUTION
西久保, 開 ,
泉, 雄大 ,
藤井, 健太郎 ,
松本, 義久横谷, 明徳
It has been recognized that activation or inactivation of DNA repair proteins is regulated by undergoing phosphorylation of certain amino acid residues. XRCC4 also undergoes phosphorylation of its several sites by DNA-PK in the DNA double strand break repair pathway (NHEJ). The phosphorylation might cause a change of static electric charge at the amino acid residues, resulting conformational alteration of the whole protein structure to permit the protein accessibility to the strand break terminus through the charge re-distribution in the protein. So far, crystal structure analysis of XRCC4 has been performed, but there is no data on the full-length of XRCC4 because of difficulty of crystallization of about 100 residues in the C terminal which includes several targets of phosphorylation. Instead of crystallography, we have applied circular dichroism (CD) spectral analysis in a vacuum UV region. CD spectral analysis allows us to analyze the full-length of the protein structure in solution. For the first step, we performed CD spectral analysis of unmodified full-length XRCC4. CD spectral data suggests that the relative fraction of the -strand is significantly larger than that reported by the crystallography. The evidence shows that structural aspects of the full length of the proteins are important to understand the conformational changes of the phosphorylation and their roles in DNA repair processes.
MICROS 2017 - 17th International Symposium on Microdosimetry 参加