acetyl-L-glutamate

• 分子结构分类: 有机化合物 - 有机酸及其衍生物 - 羧酸及其衍生物
• 英文名称: acetyl-L-glutamate
• 英文别名: (2S)-2-acetamidopentanedioate
• 化学式: C7H9NO5-2
• 分子量: 187.15
• InChiKey: RFMMMVDNIPUKGG-YFKPBYRVSA-L

计算性质

• 辛醇/水分配系数(LogP)：
  -0.5
• 重原子数：
  13
• 可旋转键数：
  3
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.57
• 拓扑面积：
  109
• 氢给体数：
  1
• 氢受体数：
  5

反应信息

• 作为反应物：
  描述：

  adenosine 5'-triphosphate 、 acetyl-L-glutamate 生成 adenosine 5'-diphosphate 、 N-acetyl-L-gamma-glutamyl phosphate(3-)
  参考文献：
  名称：

  大肠杆菌乙酰谷氨酸激酶和天冬氨酸激酶III的定点诱变探测这些氨基酸激酶家族酶的催化和底物结合机制，并允许对天冬氨酸激酶进行三维建模。

  摘要：

  我们使用定点诱变测试了基于N-乙酰基-L-谷氨酸激酶（NAGK）的X射线结构的预测，即氨基酸激酶蛋白家族的范例，该预测关于特定残基在底物结合和分离中的作用。催化。突变K8R和D162E分别使V（s = infinity）降低了100倍和1000倍，这与K8催化磷酸基转移和D162组成了催化基团的预测相符。R66K和N158Q选择性地将K（m）（Asp）增加3至4个数量级，这与R66和N158与NAG的Cα取代基的结合相一致。天冬氨酸激酶III（AKIII磷酸化天冬氨酸而不是乙酰谷氨酸）的平行诱变，这是另一个未知3-D结构的重要氨基酸激酶家族成员，在AKIII中鉴定出两个残基，即K8和D202，它们似乎起着类似于NAGK的K8和D162的作用，并支持E119和R198（类似于NAGK的R66和N158）参与氨基酸底物的结合，显然分别与α-天门冬氨酸的NH（3）（+）和α-COO（-）。这些结

  DOI：

  10.1016/j.jmb.2003.09.038
• 作为产物：
  描述：

  2-氨基戊二酸酯 、 (S)-2-乙酰氨基-5-氨基戊酸 生成 L-ornithinium(1+) 、 acetyl-L-glutamate
  参考文献：
  名称：

  嗜热微生物单和双功能鸟氨酸乙酰基转移酶的表征和动力学机理。

  摘要：

  已经从嗜热原核生物中分离出了编码N2-乙酰基-L-鸟氨酸N-乙酰基转移酶L-谷氨酸N-乙酰基转移酶的argJ基因：古细菌Methanoccocus jannaschii和嗜热菌neapolitana和嗜热脂肪芽孢杆菌。古生菌argJ仅补充大肠杆菌argE突变体（缺乏乙酰鸟氨酸酶，催化线性生物合成途径的第五步），而细菌基因另外补充argA突变体（缺乏N-乙酰谷氨酸合成酶，即途径的第一个酶）。与这些体内数据一致，纯化的詹氏甲烷八叠球菌的带有His标签的ArgJ酶仅催化N2-乙酰鸟氨酸转化为鸟氨酸，而T. neapolitana和B。嗜热脂肪热菌ArgJ还使用乙酰辅酶A作为乙酰基供体，催化谷氨酸转化为N-乙酰谷氨酸。因此，詹氏甲烷球菌ArgJ是一种单功能酶，而T. neapolitana和嗜热脂肪芽孢杆菌编码的ArgJ是双功能酶。动力学数据表明，在所有三种嗜热生物中，ArgJ介导的催化遵循乒乓双

  DOI：

  10.1046/j.1432-1327.2000.01593.x

文献信息

• Arginine Biosynthesis in <i>Thermotoga maritima</i> : Characterization of the Arginine-Sensitive <i>N</i> -Acetyl- <scp>l</scp> -Glutamate Kinase
  作者：M. Leonor Fernández-Murga、Fernando Gil-Ortiz、José L. Llácer、Vicente Rubio

  DOI：10.1128/jb.186.18.6142-6149.2004

  日期：2004.9.15

  To help clarify the control of arginine synthesis in Thermotoga maritima , the putative gene ( argB ) for N -acetyl- l -glutamate kinase (NAGK) from this microorganism was cloned and overexpressed, and the resulting protein was purified and shown to be a highly thermostable and specific NAGK that is potently and selectively inhibited by arginine. Therefore, NAGK is in T. maritima the feedback control point of arginine synthesis, a process that in this organism involves acetyl group recycling and appears not to involve classical acetylglutamate synthase. The inhibition of NAGK by arginine was found to be pH independent and to depend sigmoidally on the concentration of arginine, with a Hill coefficient ( N ) of ∼4, and the 50% inhibitory arginine concentration (I _0.5 ) was shown to increase with temperature, approaching above 65°C the I _0.50 observed at 37°C with the mesophilic NAGK of Pseudomonas aeruginosa (the best-studied arginine-inhibitable NAGK). At 75°C, the inhibition by arginine of T. maritima NAGK was due to a large increase in the K _m for acetylglutamate triggered by the inhibitor, but at 37°C arginine also substantially decreased the V _max of the enzyme. The NAGKs of T. maritima and P. aeruginosa behaved in gel filtration as hexamers, justifying the sigmoidicity and high Hill coefficient of arginine inhibition, and arginine or the substrates failed to disaggregate these enzymes. In contrast, Escherichia coli NAGK is not inhibited by arginine and is dimeric, and thus the hexameric architecture may be an important determinant of arginine sensitivity. Potential thermostability determinants of T. maritima NAGK are also discussed.

  摘要 为了帮助阐明精氨酸合成在 精氨酸合成的控制 的推定基因 ( argB ）的 N -乙酰基- l 克隆并过表达了该微生物中的 N -乙酰-l-谷氨酸激酶（NAGK），纯化后的蛋白质被证明是一种高热稳定性和特异性的 NAGK，可被精氨酸有效地选择性抑制。因此，NAGK 在 T. maritima 精氨酸合成的反馈控制点，该过程涉及乙酰基再循环，似乎不涉及经典的乙酰谷氨酸合成酶。研究发现，精氨酸对 NAGK 的抑制作用与 pH 值无关，并与精氨酸的浓度成正比例关系，希尔系数 ( N ）为 ∼4，精氨酸的 50%抑制浓度（I 0.5 ）随温度升高而增加，当温度超过 65°C 时，I 0.50 在 37°C 时观察到的嗜中性 NAGK 铜绿假单胞菌 (精氨酸可抑制的 NAGK）在 37°C 时观察到的 I 0.50。在 75°C 时，精氨酸对 T. maritima NAGK 受精氨酸抑制的原因是 K m 的大幅增加，但在 37°C 时，精氨酸也大幅降低了乙酰谷氨酸的 V 最大值 的最大值。海洋生物的 NAGKs 和 和 铜绿微囊藻 在凝胶过滤中表现为六聚体，证明了精氨酸抑制作用的西格玛性和高希尔系数，精氨酸或底物未能分解这些酶。与此形成鲜明对比的是 大肠杆菌 NAGK 不受精氨酸抑制，而且是二聚体，因此六聚体结构可能是决定精氨酸敏感性的重要因素。T. maritima 的潜在热稳定性决定因素 T. maritima NAGK 的潜在热稳定性决定因素进行了讨论。
• Phosphorylation Mechanism of <i>N</i>-Acetyl-<scp>l</scp>-glutamate Kinase, a QM/MM Study
  作者：James McClory、Gui-Xiang Hu、Jian-Wei Zou、David J. Timson、Meilan Huang

  DOI：10.1021/acs.jpcb.9b00547

  日期：2019.4.4

  closed conformation, which is predominantly controlled by an interaction between Arg98 and the α-COO- of NAG. Lys41 is found to guide phosphate transfer through the interactions with the β-,γ-, and γ-phosphate oxygen atoms of adenosine 5'-triphosphate surrounded by two highly conserved glycine residues (Gly44 and Gly76), while Arg98 helps to position the NAG substrate in the catalytic site, which facilitates

  在微生物和植物中，N-乙酰基-1-谷氨酸激酶（NAGK）催化L-精氨酸合成的第二步，即N-乙酰基-1-谷氨酸的磷酸化（NAG），得到N-乙酰基-1-谷氨酸-5 -磷酸盐。NAGK仅存在于微生物和植物中，而在哺乳动物中却不存在，这使其成为抗微生物或杀生物剂开发的有吸引力的靶标。了解NAGK的底物结合模式和反应机理对于靶向该激酶以开发潜在疗法至关重要。在此，基于分子动力学模拟，通过比较在存在和不存在NAG底物的情况下NAGK的构象变化，研究了底物结合模式。我们发现，通过底物结合，涉及NAGK中三个环的激酶催化位点呈现出封闭的构象，它主要受Arg98和NAG的α-COO-相互作用的控制。发现Lys41通过与5'-三磷酸腺苷的β-，γ-和γ-磷酸氧原子相互作用而引导磷酸盐转移，所述氧原子被两个高度保守的甘氨酸残基（Gly44和Gly76）包围，而Arg98有助于定位NAG在催化部位的底物，这有助于
• Crystal Structure of the N-Acetyltransferase Domain of Human N-Acetyl-L-Glutamate Synthase in Complex with N-Acetyl-L-Glutamate Provides Insights into Its Catalytic and Regulatory Mechanisms
  作者：Gengxiang Zhao、Zhongmin Jin、Norma M. Allewell、Mendel Tuchman、Dashuang Shi

  DOI：10.1371/journal.pone.0070369

  日期：——

  N-acetylglutamate synthase (NAGS) catalyzes the conversion of AcCoA and L-glutamate to CoA and N-acetyl-L-glutamate (NAG), an obligate cofactor for carbamyl phosphate synthetase I (CPSI) in the urea cycle. NAGS deficiency results in elevated levels of plasma ammonia which is neurotoxic. We report herein the first crystal structure of human NAGS, that of the catalytic N-acetyltransferase (hNAT) domain with N-acetyl-L-glutamate bound at 2.1 Å resolution. Functional studies indicate that the hNAT domain retains catalytic activity in the absence of the amino acid kinase (AAK) domain. Instead, the major functions of the AAK domain appear to be providing a binding site for the allosteric activator, L-arginine, and an N-terminal proline-rich motif that is likely to function in signal transduction to CPS1. Crystalline hNAT forms a dimer similar to the NAT-NAT dimers that form in crystals of bifunctional N-acetylglutamate synthase/kinase (NAGS/K) from Maricaulis maris and also exists as a dimer in solution. The structure of the NAG binding site, in combination with mutagenesis studies, provide insights into the catalytic mechanism. We also show that native NAGS from human and mouse exists in tetrameric form, similar to those of bifunctional NAGS/K.

  N-乙酰谷氨酸合成酶（NAGS）催化AcCoA和L-谷氨酸转化为CoA和N-乙酰-L-谷氨酸（NAG），后者是尿素循环中氨基甲酰磷酸合成酶I（CPSI）的必需辅助因子。NAGS缺乏会导致血氨水平升高，从而产生神经毒性。本文报道了人类NAGS的第一个晶体结构，即催化N-乙酰转移酶（hNAT）结构域与N-乙酰-L-谷氨酸结合的晶体结构，分辨率为2.1 Å。功能研究表明，在没有氨基酸激酶（AAK）结构域的情况下，hNAT结构域仍保留催化活性。相反，AAK结构域的主要功能似乎是提供变构激活剂L-精氨酸的结合位点，以及一个N端富含脯氨酸的基序，该基序可能用于向CPS1传递信号。结晶的hNAT形成二聚体，类似于在海洋丝毛虫（Maricaulis maris）双功能N-乙酰谷氨酸合成酶/激酶（NAGS/K）晶体中形成的NAT-NAT二聚体，并且在溶液中也以二聚体的形式存在。结合突变研究，NAG结合位点的结构为催化机制提供了见解。我们还发现，人类和小鼠的天然NAGS以四聚体的形式存在，类似于双功能NAGS/K。
• Identification, cloning and expression of the mouse N-acetylglutamate synthase gene
  作者：Ljubica CALDOVIC、Hiroki MORIZONO、Xiaolin YU、Mark THOMPSON、Dashuang SHI、Rene GALLEGOS、Norma M. ALLEWELL、Michael H. MALAMY、Mendel TUCHMAN

  DOI：10.1042/bj20020161

  日期：2002.6.15

  In ureotelic animals, N-acetylglutamate (NAG) is an essential allosteric activator of carbamylphosphate synthetase I (CPSI), the first enzyme in the urea cycle. NAG synthase (NAGS; EC 2.3.1.1) catalyses the formation of NAG from glutamate and acetyl-CoA in liver and intestinal mitochondria. This enzyme is supposed to regulate ureagenesis by producing variable amounts of NAG, thus modulating CPSI activity. Moreover, inherited deficiencies in NAGS have been associated with hyperammonaemia, probably due to the loss of CPSI activity. Although the existence of the NAGS protein in mammals has been known for decades, the gene has remained elusive. We identified the mouse (Mus musculus) and human NAGS genes using their similarity to the respective Neurospora crassa gene. NAGS was cloned from a mouse liver cDNA library and was found to encode a 2.3kb message, highly expressed in liver and small intestine with lower expression levels in kidney, spleen and testis. The deduced amino acid sequence contains a putative mitochondrial targeting signal at the N-terminus. The cDNA sequence complements an argA (NAGS)-deficient Escherichia coli strain, reversing its arginine auxotrophy. His-tagged versions of the pre-protein and two putative mature proteins were each overexpressed in E. coli, and purified to apparent homogeneity by using a nickel-affinity column. The pre-protein and the two putative mature proteins catalysed the NAGS reaction but one of the putative mature enzymes had significantly higher activity than the pre-protein. The addition of l-arginine increased the catalytic activity of the purified recombinant NAGS enzymes by approx. 2–6-fold.

  在尿素动物中，N-乙酰谷氨酸（NAG）是尿素循环中第一个酶--碳酰磷酸合成酶 I（CPSI）--的重要异位激活剂。NAG 合成酶（NAGS；EC 2.3.1.1）在肝脏和肠道线粒体中催化谷氨酸和乙酰-CoA 形成 NAG。这种酶应该通过产生不同数量的 NAG 来调节尿原生成，从而调节 CPSI 的活性。此外，遗传性 NAGS 缺乏症与高氨血症有关，这可能是由于 CPSI 活性丧失所致。尽管人们知道哺乳动物中存在 NAGS 蛋白已经有几十年了，但该基因仍然难以捉摸。我们利用小鼠（Mus musculus）和人类 NAGS 基因与各自的蟋蟀神经孢子（Neurospora crassa）基因的相似性，确定了小鼠（Mus musculus）和人类的 NAGS 基因。我们从小鼠肝脏 cDNA 文库中克隆出了 NAGS 基因，发现该基因编码 2.3kb 的信息，在肝脏和小肠中高度表达，而在肾脏、脾脏和睾丸中表达水平较低。推导出的氨基酸序列在 N 端包含一个假定的线粒体靶向信号。cDNA 序列补充了 argA（NAGS）缺陷的大肠杆菌菌株，逆转了其精氨酸辅助营养状态。前蛋白和两种推定成熟蛋白的 His 标记版本分别在大肠杆菌中过表达，并通过镍亲和柱纯化至明显均一。前蛋白和两种推测的成熟蛋白都能催化 NAGS 反应，但其中一种推测的成熟酶的活性明显高于前蛋白。加入精氨酸可使纯化的重组 NAGS 酶的催化活性提高约 2-6 倍。
• Functional Characterization of a Novel ArgA from <i>Mycobacterium tuberculosis</i>
  作者：James C. Errey、John S. Blanchard

  DOI：10.1128/jb.187.9.3039-3044.2005

  日期：2005.5

  The Mycobacterium tuberculosis gene Rv2747 encodes a novel 19-kDa ArgA that catalyzes the initial step in l -arginine biosynthesis, namely the conversion of l -glutamate to α- N -acetyl- l -glutamate. Initial velocity studies reveal that Rv2747 proceeds through a sequential kinetic mechanism, with K _m values of 280 mM for l -glutamine and 150 μM for acetyl-coenzyme A and with a k _cat value of 200 min ⁻¹ . Initial velocity studies with l -glutamate showed that even at concentrations of 600 mM, saturation was not observed. Therefore, only a k _cat / K _m value of 125 M ⁻¹ min ⁻¹ can be calculated. Inhibition studies reveal that the enzyme is strongly regulated by l -arginine, the end product of the pathway (50% inhibitory concentration, 26 μM). The enzyme was completely inhibited by 500 μM arginine, with a Hill coefficient of 0.60, indicating negatively cooperative binding of l -arginine.

  摘要 结核分枝杆菌 结核分枝杆菌 基因 Rv2747 编码一种新型的 19 kDa ArgA，它能催化 l -精氨酸生物合成的第一步，即将 l -谷氨酸转化为 α- N -乙酰基- l -谷氨酸。初步的速度研究表明，Rv2747 通过顺序动力学机制进行，其中 K m 值为 280 毫摩尔 l -谷氨酰胺的 K m 值为 280 毫摩尔，乙酰辅酶 A 的 K m 值为 150 微摩尔。 k cat 值为 200 min -1 .用 l -谷氨酸的初步速度研究表明，即使浓度为 600 毫摩尔，也没有观察到饱和状态。因此，只有 a k cat / K m 125 M 的值 -1 min -1 可以计算出来。抑制研究表明，该酶受到以下因素的强烈调节 l -精氨酸的强烈调节（50% 抑制浓度，26 μM）。该酶被 500 μM 精氨酸完全抑制，希尔系数为 0.60，表明精氨酸与 l -精氨酸之间存在负作用结合。 l -精氨酸的负协同结合。