Combinatorial Multinuclear NMR and X-ray Diffraction Studies of Uranium(VI)-Nucleotide Complexes

Abstract

The complex formation of uranium(VI) with four nucleotides, adenosine- (AMP), guanosine- (GMP), uridine- (UMP), and cytidine-monophosphate (CMP), has been studied in the alkaline pH range (8.5-12) by (1)H, (31)P, (13)C, and (17)O NMR spectroscopy, providing spectral integral, chemical shift, homo- and heteronuclear coupling, and diffusion coefficient data. We find that two and only two complexes are formed with all ligands in the investigated pH region independently of the total uranium(VI) and ligand concentrations. Although the coordination of the 5'-phosphate group and the 2'- and 3'-hydroxyl groups of the sugar unit to the uranyl ions is similar to that proposed earlier ("Feldman complex"), the number and the structures of the complexes are different. The uranium-to-nucleotide ratio is 6:4 in one of the complexes and 3:3 in the other one, as unambiguously determined by a combinatorial approach using a systematic variation of the ratio of two ligands in ternary uranium(VI)-nucleotide systems. The structure of the 3:3 complex has been determined by single-crystal diffraction as well, and the results confirm the structure proposed by NMR in aqueous solution. The results have important implications on the synthesis of oligonucleotides.

Supramolecular self-assembly of nucleotide–metal coordination complexes: From simple molecules to nanomaterials

“…They exhibit good affinity for high valence metal ions in basic conditions (pH = 8.5-12), such as VO 2+ , UO 2 2+ , Sn 4+ , Sb 5+ , and Sb 3+ [44,45,[47][48][49].…”

“…19a) [45], which is formed via the coordination of the 5-phosphate group and 2-and 3-hydroxyl groups of the sugar unit with central ions at pH ≈ 10. The X-ray single crystal diffraction analysis showed that the crystallographic unit cell contains two symmetryindependent trinuclear U(VI)-AMP molecules (A and B) with different orientations, as well as sodium counter ions and water molecules.…”

Nucleic Acid-Metal Ion Interactions in the Solid State

“…Interestingly, this is also the case for [Na(5'-dAMPH)]·6H 2 O [ 37 ] , despite the different crystal packings. In the two sodium salts of a pentamolybdate complex of 5'-AMPH [ 29 ] and an uranium(VI) complex of 5'-AMP [ 30 ] , Na + ions bind solely to the phosphate groups of nucleotide molecules in the [(Mo 5 O 15 )(5'-AMPH) 2 ] 2-fragment [ 29 ] or in the trimeric [(UO 2 ) 3 (O)(5'-AMP) 3 ] -framework [ 30 ] , forming an O(P)-Na-O(W)-Na-O(P) linkage (where O(P) and O(W) denote phosphate oxygen and water oxygen, respectively) in the former [ 29 ] or a Na-O( P) bond for each of the AMP molecules in the latter [ 30 ] . Crystal structures of fi ve (Li + , Na + , K + , Ca 2+ , and Mg 2+ ) salts of 2'-AMP are reported [ 31 ] ; results on metal complexes with a 2'-nucleotide are quite scarce, to date only [Cu(2'-GMP)(H 2 O) 3 ] is reported [ 38 ] .…”

“…Each of partially occupied six Na + ions is connected to one of the [ 30 ] phosphate oxygens in each of six AMP molecules, which adopts gg and anti conformations.…”

“…This Ni 2+ -5'-AMP complex is of particular importance because it provides a rare but clear example showing that the amino group is able to form a hydrogen bond with the ligating water molecule, which eventually acts here as an H-bonding acceptor in contrast to its usual participation as a H-bonding donor, since normally the two hydrogen atoms point outward to lie nearly in the equatorial coordination plane [ 22 ] . [ 30 ] , provide two novel types of structures for metalnucleotide binary system complexes, that is, "( 6 ) a phosphate-only metal bonding" for the former and "( 7 ) a trimeric structure with the metal bonding to both the sugar and phosphate" for the latter. [ 6- [ 54 ] and thus, the AMP molecule behaves here as a phosphate derivative.…”