Recognition promoted by Zn²⁺ between phenanthroline bridging polyaza ligands and nucleotides — Zn²⁺ acts as ‘messenger’ between the receptor and substrate

Abstract

The stability constants of the supramolecular complexes formed between L ((a,b,c,d)) or their Zn(2+) complexes, and adenosine 5'-triphosphate (ATP) in aqueous solution were determined by potentiometric titrations (25 degrees C, I = 0.1 mol dm(-3) KNO(3)). The results show that protonated aliphatic-substituted L (a,d) and aromatic-substituted L (b,c) ligands and/or Zn(II) ion can efficiently recognition the substrate, ATP. All of the equilibrium studies, (1)H and (31)P nuclear magnetic resonance spectra indicate that multiple interactions, including coordination, pi-stacking, ion-pairing, H-bonding, and possible ion-pi-donor, hydrophobic and even van der Waals interactions exist in the Zn(II)-L-ATP systems. On the other hand, the recognition of the substrates by the protonated ligands was significantly promoted by the addition of Zn(II), which leads to coordination competition between the mixed ligands, L and nucleotide. In Zn(II)/L/ATP systems the tendency for phosphate chain to receive proton and metal ion increases, facilitating the cleavage of the phosphate chain of the nucleotide.

Potentiometric Study on Complexation of Divalent Transition Metal Ions with Amino Acids and Adenosine 5′-Triphosphate

“…Many studies that have been made reported that ATP could bind to metal(II) ions with three donor atoms. 9,13,15 The first two of these atoms are the βand γ-phosphate oxygen atoms, and the third atom is the N (7) nitrogen atom in adenine. The stability of the MA complex in the Cu(II):ATP system is very high, whereas the stability of the MAH complex is very low.…”

“…It has been noted that the N(7) nitrogen atom binds to the metal weakly in Zn(II):ATP complexes. 15 The potentiometric titrations of (1:1) and (1:2) M(II):aa systems have been carried out under the same experimental conditions. In the Ni(II):aa Cu(II):aa systems, m 2.0 has been observed as the inflection point (Figures 2 and 3, curve IV).…”

“…4 Thus, considerable interest has been focused on the study of binary and ternary metal complexes formed with ATP and some secondary ligands. [5][6][7][8][9][10][11][12][13][14][15][16] Aspartic acid (Asp) and glutamic acid (Glu) are dicarboxylic amino acids. Containing one amino and two carboxyl groups, Asp and Glu can act as tridentate ligands.…”

A supramolecular optic sensor for selective recognition AMP

“…Progress in this area would require new strategies for the selective recognition and subsequent signaling of the event under physiological pH conditions. In previous reported literature, the recognition of adenosine was focused on supramolecular catalysis area at certain pH condition [21,22]. In this paper, we reported the recognition of adenosine in neutral medium.…”

A Systematic Evaluation of Molecular Recognition Phenomena. Part 5. Selective Binding of Tripolyphosphate and ATP to Isomeric Hexaazamacrocyclic Ligands Containing Xylylic Spacers

“…Nevertheless, a growing body of research work related to anion coordination is now emerging, including the recognition of halides [15][16][17][18][19][20][21][22][23][24][25][26][27], phosphates and nucleotides [5,, nucleic acids [46], carboxylates [21-25, 39, 45, 47-56], nitrates [18-23, 25, 27', 57-60] and sulfates [18-23, 25, 27, 38, 39, 59, 61], mainly by organic receptors. In addition, a number of studies also describe the recognition phenomena between metalloreceptors and anions such as phosphates [32,[62][63][64][65][66][67], carboxylates [67][68][69], nucleic acids [70][71][72][73], nucleobases and nucleotides [74][75][76].…”