研究人员报告了酿酒酵母INO80与六聚体或核小体结合的结构。INO80与这两种底物结合的方向大不相同。在六聚体上，INO80将其ATP酶亚基Ino80放置在超螺旋位置-2（SHL-2）上，而不是之前在核小体上看到的SHL-6和SHL-7。这些研究结果表明，INO80在六聚体上的作用类似于其他重塑因子在核小体上的作用，因此Ino80在SHL-2附近的活性最高。SHL-2位置对INO80重塑核小体也起着关键作用。
总之，INO80用于六聚体优先滑动的机制适应性意味着核小体颗粒发挥着相当大的调控作用。
据了解，与其他染色质重塑因子不同，INO80优先调动六聚体，因为六聚体可以在转录过程中形成。为什么INO80更喜欢六聚体而不是核小体，目前仍不清楚。
附：英文原文
Title: Reorientation of INO80 on hexasomes reveals basis for mechanistic versatility
Author: Hao Wu, Elise N. Muoz, Laura J. Hsieh, Un Seng Chio, Muryam A. Gourdet, Geeta J. Narlikar, Yifan Cheng
Issue&Volume: 2023-07-21
Abstract: Unlike other chromatin remodelers, INO80 preferentially mobilizes hexasomes, which can form during transcription. Why INO80 prefers hexasomes over nucleosomes remains unclear. Here, we report structures of Saccharomyces cerevisiae INO80 bound to a hexasome or a nucleosome. INO80 binds the two substrates in substantially different orientations. On a hexasome, INO80 places its ATPase subunit, Ino80, at superhelical location –2 (SHL –2), in contrast to SHL –6 and SHL –7, as previously seen on nucleosomes. Our results suggest that INO80 action on hexasomes resembles action by other remodelers on nucleosomes such that Ino80 is maximally active near SHL –2. The SHL –2 position also plays a critical role for nucleosome remodeling by INO80. Overall, the mechanistic adaptations used by INO80 for preferential hexasome sliding imply that subnucleosomal particles play considerable regulatory roles.
DOI: adf4197
Source: https://www.science.org/doi/10.1126/science.adf4197