Crystal structure of the NG domain from the signal-recognition particle receptor FtsY
Crystal structure of the NG domain from the signal-recognition particle receptor FtsY
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DOI：
10.1038/385365a0
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发表时间：
1997-01-23
期刊：
影响因子：
64.8
通讯作者：
Sinning, I
中科院分区：
文献类型：
--
作者：
Montoya, G;Svensson, C;Sinning, I
新合成的用于分泌或掺入膜的蛋白质通过由信号识别颗粒 (SRP) 及其受体 (1,2) 组成的普遍系统靶向膜易位机制。 SRP 受体和 SRP 内结合信号序列的蛋白质都含有 GTPases(3,4)。这两种蛋白质与 SRP 的 RNA 成分一起形成复合物 (5-7)，从而调节彼此的 GTP 酶活性 (8)。在这里，我们以 2.2 埃的分辨率报道了 FtsY（大肠杆菌 (9) 的 SRP 受体的功能同源物）含有 GTP 酶的部分的结构，没有结合核苷酸。这个所谓的 NG 结构域与 Ras 相关 GTP 酶相似，并且具有 SRP 型 GTP 酶特有的特征 (10)，例如单独的氨基末端结构域、p21(ras) (Ras) 效应结构域内的插入 (11) 以及开放的 GTP 结合区。该结构解释了 FtsY 对 GTP 的低亲和力，并表明核苷酸结合时可能发生重排。它还识别了可能参与域之间信号传输以及与调节蛋白相互作用的区域。
Newly synthesized proteins destined either for secretion or incorporation into membranes are targeted to the membrane translocation machinery by a ubiquitous system consisting of a signal recognition particle (SRP) and its receptor(1,2). Both the SRP receptor and the protein within the SRP that binds the signal sequence contain GTPases(3,4). These two proteins, together with the RNA component of the SRP, form a complex(5-7) and thereby regulate each other's GTPase activity(8). Here we report the structure of the GTPase-containing portion of FtsY, the functional homologue of the SRP receptor of Escherichia coli(9), at 2.2 Angstrom resolution without bound nucleotide. This so-called NG domain displays similarities to the Ras-related GTPases, as well as features unique to the SRP-type GTPases(10), such as a separate aminoterminal domain, an insertion within the p21(ras) (Ras) effector domain(11), and a wide-open GTP-binding region. The structure explains the low affinity of FtsY for GTP, and suggests rearrangements that may occur on nucleotide binding. It also identifies regions potentially involved in the transmission of signals between domains and in interactions with regulatory proteins.