Zheng Jianzhou, Lu Jian, Liu Haijun, Li Jun, Chen Keping
Institute of life science, Jiangsu University, Zhenjiang, China.
Bioinformation. 2009 Sep 30;4(3):127-31. doi: 10.6026/97320630004127.
The fugu SN4TDR protein belongs to an evolutionarily conserved family, consisting of four repeat staphylococcal nuclease-like domains (SN1-SN4) at the N-terminus followed by Tudor and SN-like domains (TSN). Sequence analysis showed that the C-terminal TSN domain is composed of a complete SN-like domain interdigitated with a Tudor domain. In despite of low level of sequence identities, five SN-like domains have a few conserved amino acids that may play essential roles in the function of the protein. Computer modeling and secondary structural prediction of the SN-like domains revealed the presence of similar structural features of beta1-beta2-beta3-alpha1-beta4-beta5-alpha2-alpha3, which provides a structural basis for oligonucleotides binding. The loop region L(3alpha) for binding sites between beta3 and alpha1 of SN-like domains are different from human p100, implying the divergence in the structures of binding sites. These results indicate that fugu SN4TDR may bind methylated ligands and/or oligonucleotides through its distant domains.
河豚SN4TDR蛋白属于一个进化上保守的家族，在其N端由四个重复的葡萄球菌核酸酶样结构域（SN1 - SN4）组成，随后是Tudor和SN样结构域（TSN）。序列分析表明，C端TSN结构域由一个完整的SN样结构域与一个Tudor结构域相互交错组成。尽管序列同一性水平较低，但五个SN样结构域有一些保守氨基酸，可能在蛋白质功能中起关键作用。对SN样结构域的计算机建模和二级结构预测显示存在类似的β1-β2-β3-α1-β4-β5-α2-α3结构特征，这为寡核苷酸结合提供了结构基础。SN样结构域β3和α1之间结合位点的环区L(3α)与人p100不同，这意味着结合位点结构存在差异。这些结果表明，河豚SN4TDR可能通过其远结构域结合甲基化配体和/或寡核苷酸。
