Cort J R, Yee A, Edwards A M, Arrowsmith C H, Kennedy M A
Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, EMSL 2569 K8-98, Richland, WA 99352, USA.
J Mol Biol. 2000 Sep 8;302(1):189-203. doi: 10.1006/jmbi.2000.4052.
The structure of MTH538, a previously uncharacterized hypothetical protein from Methanobacterium thermoautotrophicum, has been determined by NMR spectroscopy. MTH538 is one of numerous structural genomics targets selected in a genome-wide survey of uncharacterized sequences from this organism. MTH538 is a so-called singleton, a sequence not closely related to any other (known) sequences. The structure of MTH538 closely resembles the known structures of receiver domains from two component response regulator systems, such as CheY, and is similar to the structures of flavodoxins and GTP-binding proteins. Tests on MTH538 for characteristic activities of CheY and flavodoxin were negative. MTH538 did not become phosphorylated in the presence of acetyl phosphate and Mg(2+), although it appeared to bind Mg(2+). MTH538 also did not bind flavin mononucleotide (FMN) or coenzyme F(420). Nevertheless, sequence and structure parallels between MTH538/CheY and two families of ATPase/phosphatase proteins suggest that MTH538 may have a role in a phosphorylation-independent two-component response regulator system.
通过核磁共振光谱法测定了嗜热自养甲烷杆菌中一种此前未被表征的假定蛋白MTH538的结构。MTH538是在对该生物体未表征序列进行全基因组调查时选择的众多结构基因组学目标之一。MTH538是一种所谓的单拷贝基因，其序列与任何其他（已知）序列都没有密切关系。MTH538的结构与双组分应答调节系统中接收结构域的已知结构非常相似，如CheY，并且与黄素氧还蛋白和GTP结合蛋白的结构相似。对MTH538进行CheY和黄素氧还蛋白特征活性测试的结果为阴性。尽管MTH538似乎能结合Mg(2+)，但在乙酰磷酸和Mg(2+)存在的情况下它并未发生磷酸化。MTH538也不结合黄素单核苷酸（FMN）或辅酶F(420)。然而，MTH538/CheY与两个ATP酶/磷酸酶蛋白家族之间的序列和结构相似性表明，MTH538可能在一个不依赖磷酸化的双组分应答调节系统中发挥作用。
