Mechanism of disruption of the Amt-GlnK complex by P(II)-mediated sensing of 2-oxoglutarate.
Mechanism of disruption of the Amt-GlnK complex by P(II)-mediated sensing of 2-oxoglutarate.
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DOI：
10.1371/journal.pone.0026327
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发表时间：
2011
期刊：
影响因子：
3.7
通讯作者：
Andrade SL
中科院分区：
文献类型：
--
作者：
Maier S;Schleberger P;Lü W;Wacker T;Pflüger T;Litz C;Andrade SL
GlnK蛋白通过将其调节性T环插入到三聚体的转运通道中并物理地阻断底物通道来调节氨转运蛋白对铵的主动摄取。它们通过2-酮戊二酸感知细胞的氮状态，并通过以不同亲和力结合ATP和ADP来感知细胞的能量水平。极端嗜热的宽古菌闪烁古生菌具有三个GlnK蛋白，每个GlnK蛋白编码的操纵子。其中一种蛋白GlnK 2最近被发现不能结合2-OG，为了理解这一发现的意义，我们对来自A. fulgidus，GlnK3.与Af-GlnK 2相反，该蛋白能够结合ATP/2-OG和ADP以分别产生无活性和功能状态。由于蛋白质的热稳定性，我们可以观察到众所周知的灵活的T环的准确定位，并解释GlnK蛋白质与其相互作用伴侣的结合行为。这些结合事件的热力学分析，使用微量热法通过microstate建模评估显示显着差异，结合协同性相比，其他特征的PII蛋白，强调这类调节信号蛋白的多样性和适应性。
GlnK proteins regulate the active uptake of ammonium by Amt transport proteins by inserting their regulatory T-loops into the transport channels of the Amt trimer and physically blocking substrate passage. They sense the cellular nitrogen status through 2-oxoglutarate, and the energy level of the cell by binding both ATP and ADP with different affinities. The hyperthermophilic euryarchaeon Archaeoglobus fulgidus possesses three Amt proteins, each encoded in an operon with a GlnK ortholog. One of these proteins, GlnK2 was recently found to be incapable of binding 2-OG, and in order to understand the implications of this finding we conducted a detailed structural and functional analysis of a second GlnK protein from A. fulgidus, GlnK3. Contrary to Af-GlnK2 this protein was able to bind both ATP/2-OG and ADP to yield inactive and functional states, respectively. Due to the thermostable nature of the protein we could observe the exact positioning of the notoriously flexible T-loops and explain the binding behavior of GlnK proteins to their interaction partner, the Amt proteins. A thermodynamic analysis of these binding events using microcalorimetry evaluated by microstate modeling revealed significant differences in binding cooperativity compared to other characterized PII proteins, underlining the diversity and adaptability of this class of regulatory signaling proteins.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
4.8
作者：
KAMBEROV, ES;ATKINSON, MR;NINFA, AJ
通讯作者：
NINFA, AJ
DOI：
10.1073/pnas.0610348104
发表时间：
2007-01-23
影响因子：
11.1
作者：
Conroy, Matthew J.;Durand, Anne;Merrick, Mike
通讯作者：
Merrick, Mike
影响因子：
11.4
作者：
Coutts, G;Thomas, G;Merrick, M
通讯作者：
Merrick, M
DOI：
10.1073/pnas.1003587107
发表时间：
2010-05-25
影响因子：
11.1
作者：
Gruswitz, Franz;Chaudhary, Sarika;Stroud, Robert M.
通讯作者：
Stroud, Robert M.