[3P-1] ポスター3（3P-01ー3P-47）

[3P-31(WS10-4)] 相関構造生物学によるFACTを介したヒストンH3テイルの動的構造変化の解明

^○津中 康央¹, 大友 秀明¹, 森川 耿右², 西村 善文^1,3 (1.横浜市大・院・生命医科学, 2.京大・院・生命科学, 3.広島大・院・統合生命)

The FACT complex, comprising SPT16 and SSRP1, conducts nucleosome reorganization. We previously revealed that the phosphorylated acidic intrinsically disordered (pAID) segment of SPT16 within FACT initially binds to the H2B N-tail detached from the nucleosomal DNA by a double strand break [Tsunaka et al., (2016) Genes Dev., 30, 673-686]. In addition, our previous cryo-EM analysis revealed the first intermediate structure of an unwrapped nucleosome with FACT, in which 112-bp DNA and pAID asymmetrically wrapped around the histone core instead of 145-bp DNA [Mayanagi et al., (2019) Sci. Rep., 9, 10183]. Using NMR, here we clarified that the histone H3 N-terminal tails invisible in the cryo-EM structure adopt two different conformations reflecting their asymmetric locations at entry/exit sites: one corresponds to the original nucleosome site buried in two DNA gyres (DNA side), whereas the other, comprising pAID and DNA, is more exposed to the solvent (pAID side) [Tsunaka et al., (2020) iScience 23, 101641]. NMR real-time monitoring showed that H3 acetylation is faster on the pAID side than on the DNA side. NMR spectroscopy and cryo-EM provide a synergistic approach to characterizing dynamic changes of histone H3 N-tails by FACT.