The crystal structure of the Escherichia coli AmtB-GlnK complex reveals how GlnK regulates the ammonia channel
The crystal structure of the Escherichia coli AmtB-GlnK complex reveals how GlnK regulates the ammonia channel
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DOI：
10.1073/pnas.0610348104
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发表时间：
2007-01-23
影响因子：
11.1
通讯作者：
Merrick, Mike
中科院分区：
文献类型：
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作者：
Conroy, Matthew J.;Durand, Anne;Merrick, Mike
Amt蛋白是古细菌、真细菌、真菌和植物中普遍存在的氨传导通道。在大肠杆菌中，先前的研究表明，P-II信号转导蛋白GlnK与氨通道AmtB的结合可以调节氨通道，从而控制氨内流，以响应细胞内氮状态。在这里，我们以2.5埃的分辨率描述了AmtB和GlnK之间配合物的晶体结构。这种P-II复合物与其靶标之一的结构揭示了AmtB和GInK的生理相关构象。GInK几乎完全通过含有Y51 （t环）的长表面环与AmtB相互作用，其尖端深深插入细胞质孔出口，阻断氨传导。GInK的Y51也埋藏在孔出口，这解释了为什么该残基的尿苷化会阻止复合物的形成。
Amt proteins are ubiquitous channels for the conduction of ammonia in archaea, eubacteria, fungi, and plants. In Escherichia coli, previous studies have indicated that binding of the P-II signal transduction protein GlnK to the ammonia channel AmtB regulates the channel thereby controlling ammonium influx in response to the intracellular nitrogen status. Here, we describe the crystal structure of the complex between AmtB and GlnK at a resolution of 2.5 angstrom. This structure of P-II in a complex with one of its targets reveals physiologically relevant conformations of both AmtB and GInK. GInK interacts with AmtB almost exclusively via a long surface loop containing Y51 (T-loop), the tip of which inserts deeply into the cytoplasmic pore exit, blocking ammonia conduction. Y51 of GInK is also buried in the pore exit, explaining why uridylylation of this residue prevents complex formation.