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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Differential effects of Mg(II) and N-alpha-4-tosyl-L-arginine methyl ester hydrochloride on the recognition and catalysis in ATP hydrolysis
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Differential effects of Mg(II) and N-alpha-4-tosyl-L-arginine methyl ester hydrochloride on the recognition and catalysis in ATP hydrolysis

机译：Mg（II）和N-α-4-甲苯磺酰基-L-精氨酸甲酯盐酸盐对ATP水解中识别和催化的差异作用

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The supramolecular interactions of Mg(II) and N-alpha-4-tosyl-L-arginine methyl ester hydrochloride (TAME) with ATP have been investigated using H-1 and P-31 NMR spectra. Furthermore, the hydrolysis of ATP catalyzed by Mg(II) and TAME has been studied at 60 degrees C and pH 7 using 31P NMR spectra. In the Mg(II)-ATP-TAME ternary system, the binding interaction of Mg2+ with ATP involves not only N1 and N7 in the adenine ring but also beta- and gamma-phosphate of ATP. The binding forces are mainly electrostatic interaction and cation (Mg2+)-pi interaction. The guanidinium group and the aromatic ring of TAME interacts with ATP by beta and gamma phosphate and the adenine ring of ATP. The binding forces are mainly electrostatic interactions and pi-pi stacking. A significant difference between the binary and the ternary system indicates that TAME is essential to the stablization of the intermediate. Kinetic studies show that the hydrolysis rate constant of ATP is 2.16 x 10(-2) h(-1) at pH 7 in the Mg(II)-TAME-ATP ternary system. The Mg(II) ion and TAME can accelerate the ATP hydrolysis process. A possible mechanism has been proposed that the hydrolysis occurs through an addition-elimination, in which the phosphoramidate intermediate was observed at 3.21 ppm in the P-31 NMR of the ternary system. These results provide further information concerning the effect of the key amino acid residue and metal ions as cofactors of ATPase on ATP synthesis/hydrolysis at the molecular level.
机译：使用H-1和P-31 NMR光谱研究了Mg（II）和N-α-4-甲苯磺酰基-L-精氨酸甲酯盐酸盐（TAME）与ATP的超分子相互作用。此外，使用31P NMR光谱研究了Mg（II）和TAME催化的ATP的水解，温度为60℃，pH为7。在Mg（II）-ATP-TAME三元系统中，Mg2 +与ATP的结合相互作用不仅涉及腺嘌呤环中的N1和N7，而且还涉及ATP的β-磷酸和γ-磷酸。结合力主要是静电相互作用和阳离子（Mg 2+）-π相互作用。 TAME的胍基和芳香环通过β和γ磷酸与ATP的腺嘌呤环与ATP相互作用。结合力主要是静电相互作用和π-π堆积。二元体系和三元体系之间的显着差异表明TAME对于中间体的稳定化至关重要。动力学研究表明，在Mg（II）-TAME-ATP三元体系中，pH值为7时ATP的水解速率常数为2.16 x 10（-2）h（-1）。 Mg（II）离子和TAME可以加速ATP水解过程。已经提出了一种可能的机制，即通过加成消除发生水解，其中在三元体系的P-31 NMR中观察到氨基磷酸酯中间体的含量为3.21 ppm。这些结果提供了有关关键氨基酸残基和作为ATPase辅因子的金属离子在分子水平上对ATP合成/水解的影响的进一步信息。

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