2026-10-14T13:03:13Z https://www.scidb.cn/oai

10.57760/sciencedb.26050 2025-06-10T11:05:16Z

2025-06-10 Structural basis of nucleosome deubiquitination by the bidentate Calypso/ASX complex doi:10.57760/sciencedb.26050 en Here we report the cryo-EM structure of Drosophila Calypso/ASX complex bound to a nucleosome, revealing the molecular basis of its chromatin interaction. Unexpectedly, only one Calypso/ASX copy engages the nucleosomal substrate in a conformation analogous to that observed in human BAP1/ASXL1, while the second unit remains structurally disengaged. We further identify the C-terminal tail of Calypso as the principal determinant of substrate affinity through direct interaction with nucleosomal DNA. Together, these findings support a model in which the bidentate Calypso/ASX complex enables processive deubiquitination along chromatin through alternating or cooperative catalytic engagement. Polycomb repression; H2A119ub; Chromatin; Ubiquitin C-terminal hydrolase; PR-DUB Wang Chi Sun Fahui Zhao Heyu Zhang Nan Guan Jiali Zhou Yuxing Shuai Wentong Zheng Hui He Jun PUBLIC https://creativecommons.org/licenses/by/4.0/ dataset http://www.doi.org/10.1016/j.isci.2026.114958 Science Data Bank