Structure of a thermostable methionine adenosyltransferase from Thermus thermophilus HB27 reveals a novel fold of the flexible loop
Structure of a thermostable methionine adenosyltransferase from Thermus thermophilus HB27 reveals a novel fold of the flexible loop
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来自嗜热栖热菌 HB27 的热稳定蛋氨酸腺苷转移酶的结构揭示了柔性环的新折叠
DOI：
10.1039/c5ra27938k
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发表时间：
2016
期刊：
影响因子：
3.9
通讯作者：
Feng Yue
中科院分区：
文献类型：
--
作者：
Liu Yanhui;Wang Wenhe;Zhang Weiwei;Dong Yanan;Han Fengjiao;Raza Muslim;Liu Luo;Tan Tianwei;Feng Yue
蛋氨酸腺苷转移酶（Methionine adenosyltransferases, MATs）是合成s -腺苷蛋氨酸（S-adenosylmethionine, AdoMet）的一类酶。已经报道了几种不同物种的席的三维结构，包括细菌、古细菌和真核生物。MAT结构的一个共同特征是柔性环，它被提议作为一个动态盖子来控制底物对活性位点的访问。在这项研究中，我们以2.67 Å分辨率解析了来自Thermus thermophilus HB27 （TtMAT）的耐热MAT的x射线结构。TtMAT的四聚体组装和活性位点残基与来自大肠杆菌（EcMAT）的MAT相似。然而，TtMAT中的柔性环比EcMAT的长，并且以开放构象定义，这在已知的MAT结构中是不寻常的。此外，TtMAT的环路与其他包含有序/无序环路的mat的构象不同。对这个循环的进一步分析表明，它可能解释了TtMAT更好的热稳定性。
Methionine adenosyltransferases (MATs) are the family of enzymes which synthesize S-adenosylmethionine (AdoMet), the major biological methyl donor. Three-dimensional structures have been reported for MATs from several different species, including bacteria, archaea and eukarya. A common feature in MAT structures is a flexible loop which is proposed to serve as a dynamic lid controlling the access of substrate to the active site. In this study, we solved the X-ray structure of a thermostable MAT from Thermus thermophilus HB27 (TtMAT) at 2.67 Å resolution. Both the tetrameric assembly and the residues in the active site of TtMAT are similar to those of MAT from Escherichia coli (EcMAT). However, the flexible loop in TtMAT is longer than that of EcMAT and well-defined in an open conformation, which is unusual among known MAT structures. Moreover, the loop of TtMAT is in a conformation different from those of other MATs which contain ordered/disordered loops. A further analysis of this loop suggested that it might explain the better thermostability of TtMAT.