Differential effects of Mg(ii) and N_α-4-tosyl-l-arginine methyl ester hydrochloride on the recognition and catalysis in ATP hydrolysis

Abstract

The supramolecular interactions of Mg(ii) and N(alpha)-4-tosyl-l-arginine methyl ester hydrochloride (TAME) with ATP have been investigated using (1)H and (31)P NMR spectra. Furthermore, the hydrolysis of ATP catalyzed by Mg(ii) and TAME has been studied at 60 degrees C and pH 7 using (31)P NMR spectra. In the Mg(ii)-ATP-TAME ternary system, the binding interaction of Mg(2+) 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 (Mg(2+))-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 (31)P 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.

Metal ion binding to an RNA internal loop

“…The 31 P spectra show an overall generalized broadening upon metal ion addition. However, despite the strong overlap, a few peaks could be followed during to the β, γ-phosphates and N7 of G1 TP [35,36]. The same behaviour was recently observed in the case of D1κζ [12].…”

Effects of Metal Ions (Mg2+, Ca2+, Cd2+ and Zn2+) on Adenosine Triphosphate Hydrolysis

“…2 provide information about the interaction between the phosphate chain and the different metal ions. All experimental data of metal-ATP are similar to the Mg 2+ -ATP binary system analyzed in the previous work in detail 23 . All the conclusions outlined for Mg 2+ -ATP are also valid for Ca 2+ -ATP, Cd 2+ -ATP and Zn 2+ -ATP binary systems.…”

“…This indicates that the interaction between TAME and phosphate chain is relative weaker than the interaction between metal ions and phosphate chain 30 . Metal-ATP binary system: Mg 2+ complexation study previously performed on the binary adenosine triphosphate system indicated the formation of a 1:1 complex 23 . Analogous techniques were used in this study to determine binary and ternary systems complexation tendencies, i.e., by monitoring 1 H and 31 P chemical shifts with the different metal ions.…”

“…Adenosine-5'-triphosphate disodium salt (adenosine triphosphate) and N α -4-tosyl-L-arginine methyl ester hydrochloride were purchased from Acros organics (USA). Their structures are taken from the paper of Ma and Lu 23 . MgCl 2 •6H 2 O and other metal ion salt were purchased from Shanghai Chemical reagent Ltd. (China).…”

“…Among these studies the physicochemical character and conformational variation of L-arginine have shown very interesting behaviour both in the recognition of magnesium ion and their interaction with adenosine triphosphate. In a preceding paper, we described different effects of Mg and Ca on the recognition and catalysis in adenosine triphosphate hydrolysis 23,24 . Aiming at further knowledge on the series metal ions of the coordination chemistry of adenosine triphosphate, our group reports the results of binary and ternary metal ion (Mg 2+ , Ca 2+ , Cd 2+ and Zn 2+ ) complexes with adenosine triphosphate and Nα-4-tosyl-L-arginine methyl ester hydrochloride (TAME).…”