Structural and functional analysis of SET8, a histone H4 Lys-20 methyltransferase
Structural and functional analysis of SET8, a histone H4 Lys-20 methyltransferase
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DOI：
10.1101/gad.1318405
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发表时间：
2005-06-15
影响因子：
10.5
通讯作者：
Trievel, RC
中科院分区：
文献类型：
--
作者：
Couture, JF;Collazo, E;Trievel, RC
SET8（也称为 PR-SET7）是一种组蛋白 H4-Lys-20 特异性甲基转移酶，参与后生动物中细胞周期依赖性转录沉默和有丝分裂调节。在此，我们报告了与带有 Lys-20 的组蛋白 H4 肽和产物辅因子 S-腺苷高半胱氨酸结合的人 SET8 (hSET8) 的晶体结构。组蛋白 H4 作为延伸的平行 P 链插入底物结合裂隙中。 H4 中 Lys-20 之前的残基与 hSET8 进行广泛的盐桥、氢键和范德华相互作用，而 C 末端残基主要通过疏水性相互作用进行结合。对底物结合裂口和组蛋白 H4 的突变分析表明，与 H4 肽 N 和 C 末端残基的相互作用对于赋予底物特异性至关重要。最后，产物特异性分析表明 hSET8 是一种单甲基化酶，与其在细胞分裂过程中维持 Lys-20 单甲基化的作用一致。
SET8 (also known as PR-SET7) is a histone H4-Lys-20-specific methyltransferase that is implicated in cell- cycle-dependent transcriptional silencing and mitotic regulation in metazoans. Herein we report the crystal structure of human SET8 (hSET8) bound to a histone H4 peptide bearing Lys-20 and the product cofactor S-adenosylhomocysteine. Histone H4 intercalates in the substrate-binding cleft as an extended parallel P-strand. Residues preceding Lys-20 in H4 engage in an extensive array of salt bridge, hydrogen bond, and van der Waals interactions with hSET8, while the C-terminal residues bind through predominantly hydrophobic interactions. Mutational analysis of both the substrate-binding cleft and histone H4 reveals that interactions with residues in the N and C termini of the H4 peptide are critical for conferring substrate specificity. Finally, analysis of the product specificity indicates that hSET8 is a monomethylase, consistent with its role in the maintenance of Lys-20 monomethylation during cell division.