The essential SAS2-related acetyltransferase 1 (Esa1), as a acetyltransferase of MYST family, is indispensable for the cell cycle and transcriptional regulation. The Tudor domain consists of 60 amino acids and belongs to the Royal family, which serves as a module interacting with methylated histone and/or DNA. Although Tudor domain has been widely studied in higher eukaryotes, its structure and function remain unclear in Trypanosoma brucei (T. brucei), a protozoan unicellular parasite causing sleeping sickness in human and nagana in cattle in sub-Saharan Africa. Here, we determined a high-resolution structure of TbEsa1 presumed Tudor domain from T. brucei by X-ray crystallography. TbEsa1 Tudor domain adopts a conserved Tudor-like fold, which is comprised of a five-stranded β-barrel surrounded by two short α-helices. Furthermore, we revealed a non-specific DNA binding pattern of TbEsa1 Tudor domain. However, TbEsa1 Tudor domain showed no methyl-histone binding ability, due to the absence of key aromatic residues forming a conserved aromatic cage.

中文翻译：

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TbEsa1的晶体结构推测是布鲁氏锥虫的Tudor结构域。

必需的SAS2相关乙酰基转移酶1（Esa1）作为MYST家族的乙酰基转移酶，对于细胞周期和转录调控是必不可少的。Tudor结构域由60个氨基酸组成，属于皇家家族，其作为与甲基化组蛋白和/或DNA相互作用的模块。尽管在高级真核生物中已经广泛研究了Tudor结构域，但其结构和功能在Trypanosoma brucei（T. brucei）中仍不清楚，Trypanosoma brucei是一种原生动物单细胞寄生虫，可导致撒哈拉以南非洲牛和人的长颈鹿昏睡。在这里，我们通过X射线晶体学确定了T. Brucei推测的Tudor域的TbEsa1高分辨率结构。TbEsa1 Tudor结构域采用保守的Tudor样折叠，由五链β桶和两个短α螺旋包围。此外，我们揭示了TbEsa1 Tudor域的非特异性DNA结合模式。然而，TbEsa1 Tudor域显示没有甲基组蛋白结合能力，因为不存在形成保守芳香族笼的关键芳香族残基。