Preparation and physico-chemical properties of the ternary complexes formed between adenosine 5′-triphosphoric acid, bis(2-pyridyl)amine, and divalent metal ions. Crystal and molecular structures of the compounds containing Mg^IIand Ca^II

Abstract

Ternary compounds formed between M (Mg", Ca", Sr", Mn", Co", Cu", or Zn"), adenosine 5'-trip hosp ha te [adenosine 5'trip hosp hate (4 -) = atp] , and bis (2pyridyl ) amine (bi pyam) have been prepared. The solid compounds are crystalline and have a stoicheiometry described by the formula M (Hatp) ( Hbipyam).nH20 (n = 2-9). X-Ray powder diffraction patterns are similar. Potentiometric titrations in aqueous solution show the presence of t w o ionizable protons. Visible spectra suggest an octahedral co-ordination geometry. 1.r. spectra indicated essentially the same type of metal-ligand interactions in all the complexes and show that Hatp3-co-ordinates to the metal through the oxygen atoms of the a, PI and y phosphate groups. The ternary compounds where M = Mg" (I) or Ca" (2) have been studied by single-crystal X-ray diffraction techniques and their molecular structures determined. The two species are isostructural and can be formulated as1) and [Ca(H,O),] [Hbipyam]2[Ca(Hatp)2]-9H,0 (2). Both (1) and (2) crystallise in space group C222, (Z = 4), with a = 22.734(3), b = 10.233(3), c = 30.997(4) A for (1) and a = 22.965(3), b = 10.1 54(3), c = 32.390(4) A for (2). X-Ray diffraction data were collected on a Philips automatic diffractometer and the structures solved by direct methods using the SIR (Semi-invariant Representation) package and refined b y full-matrix least squares to final R values of 0.1 11 and 0.1 24(1 088 and 1 008 independent observed reflections) for (1) and (2) respectively. In the [ M ( H a t ~) ~l ~units the metal ions lie on a two-fold axis with an octahedral co-ordination geometry completed by the oxygen atoms of the a, PI and y phosphate groups of t w o symmetry-related Hatp3-molecules. The co-ordination polyhedron of (1) is nearly regular but in (2) it is significantly distorted. The phosphate chains have a folded configuration in both ( 1) and (2). In both complexes there are no bonding interactions between the metal ions and the adenine base. The metal atoms of the [M(H20),l2+ cations are also located on two-fold axes while the six co-ordinated water molecules form hydrogen bonds with the phosphate chains. The Hbipyam+ molecules d o not co-ordinate to the metal ions and are disordered around two-fold axes. Strong stacking interactions exist between H bipyam+ and purine rings.

Synthesis, structure, proton-nuclear magnetic resonance, and Fourier transform infrared spectroscopy of several transition and nontransition metal–adenosine-5-triphosphate complexes

“…This is indicative of a phosphate coordination mode in this series of metal-ATP complexes. The coordination of the a, P, and y phosphate oxygen atoms in M~~+ and ca2+ in several other ternary metal-ATP complexes is known from X-ray crystallography (9,10). In the spectra of the Pt-ATP complexes prepared here, the vibrations related to the phosphate group exhibited no major changes upon metal complexation (Fig.…”

“…2 and Table 4). A recent structural analysis of Mg2+ and Ca2+ complexes of ATP and dipyridineamine also exhibited the C2'-endo-anti sugar conformation in these metal complexes (10). It is interesting to note that in the ternary compounds of ATP with Cu2+ and zn2+, the sugar has C3'-endo-anti conformation (7,8), whereas in the corresponding binary complexes the sugar showed the C2'-endo-anti conformation (Table 4).…”

“…Although various spectroscopic techniques have been used (3)(4)(5)(6) to characterize the nature of metal-ATP interactions, until recently the metal ion binding to the various potential coordination sites of the ATP molecule was the subject of speculation. A recent X-ray structural analysis of ternary complexes [Cu(H2ATP)(phen)l2.7H2O (7) and [Zn(H2ATP)(bipy)12.4H20 (8) and several other complexes of Mg2+, Ca2+, ~n~+ , and Co2+ with ATP and dipyridylamine (9,10) showed that the metal-ATP binding is through the a, P, and y, phosphate oxygen atoms and that there is no interaction between the metal ion and the base adenine.…”

Effect of Free Water Molecules on the Structure of Mg-ATPDipyridylamine and Overview on Selected Metal-Adenosine Triphosphate Structures in Model Compounds and in Enzymes~!2009-08-29~!2009-12-08~!2010-02-08~!

“…The procedure for the synthesis and preparation of crystals suitable for X-ray diffraction studies was similar to that previously reported [12,13]. Crystalline DPA (34 mg, 0.2 mmol) was added by 3 mL EtOH (95% v/v) and the clear 2) were selected through the polarizing microscope, mounted on a thin glass fiber and then submitted to X-ray diffraction experiments.…”

“…/Ca 2+ -adenosine 5'-triphosphate, Mg/CaATP, that have linking interactions between the metal ions and the nucleo-tide molecule via the phosphate oxygen only, previously reported [12,13], were studied with the aim to shed light on the role of free water molecules. Room temperature data collection were done via a conventional source Siemens P4 diffractometer, and (in subsequent data collections) by using a Bruker Nonius FR 591 rotating anode with molybdenum target and a Nonius Kappa CCD with confocal focusing mirrors.…”