上海交通大学学报（医学版）2026，Vol.46Issue(6)：732-739,8.DOI:10.3969/j.issn.1674-8115.2026.06.005
人源SUV39H1-HP1α复合物识别内源核小体的冷冻电镜结构分析
Structural insights into the recognition of endogenous nucleosomes by the human SUV39H1-HP1α complex
摘要
Abstract
Objective·To analyze the three-dimensional structure of the human histone methyltransferase SUV39H1 in complex with heterochromatin protein 1α bound to the endogenous nucleosome core particle(NCPendo)through cryo-electron microscopy(cryo-EM).Methods·The human SUV39H1 gene was cloned into the pMLink vector with an N-terminal 6×His-3×Flag tag,and the human HP1α gene was cloned into the pMLink vector with an N-terminal 2×HA tag.The SUV39H1-HP1α complex was co-expressed in Expi293F mammalian suspension cells through transient transfection using polyethylenimine.The expressed complex was sequentially purified by affinity chromatography with anti-DYKDDDDK resin and glycerol gradient ultracentrifugation combined with chemical cross-linking.Subsequently,cryo-EM data collection and single-particle reconstruction were performed to obtain the three-dimensional electron density map of the SUV39H1-HP1α-NCPendo complex.AlphaFold2-predicted models were docked into the EM density using UCSF Chimera.Results·The SUV39H1-HP1α-NCPendo complex was successfully obtained with high purity by affinity chromatography and glycerol density gradient ultracentrifugation.Cryo-EM single-particle reconstruction yielded a preliminary density map of the SUV39H1-HP1α-NCPendo complex at a resolution of approximately 3.6 Å(1 Å=10-10 m).In addition to the nucleosome core particle,an extra discontinuous peripheral density was observed.Based on its size and spatial distribution,preliminary structural fitting suggested that this density may correspond to the SET domain of SUV39H1.Conclusion·The density map of the SUV39H1-HP1α-NCPendo complex was obtained by cryo-EM and single-particle reconstruction.Although the peripheral density is discontinuous and does not support reliable atomic modeling,its size and spatial features are consistent with the SET domain(including pre-SET,SET,and post-SET sub-modules)of SUV39H1.In addition,the chromo domain(CD)of SUV39H1 and HP1α were not been clearly resolved,suggesting that these regions may exhibit conformational dynamics within this complex.关键词
甲基转移酶SUV39H1/异染色质结合蛋白1α/核小体/表观遗传调控/冷冻电镜Key words
SUV39H1 methyltransferase/heterochromatin protein 1α(HP1α)/nucleosome/epigenetic regulation/cryo-electron microscopy分类
生物科学引用本文复制引用
胡琼,黄晶..人源SUV39H1-HP1α复合物识别内源核小体的冷冻电镜结构分析[J].上海交通大学学报（医学版）,2026,46(6):732-739,8.基金项目
国家自然科学基金(32022036). National Natural Science Foundation of China(32022036). （32022036）
