169 research outputs found
Tetrakis(μ-2-phenoxypropionato)-κ3 O,O′:O′;κ3 O:O,O′,κ4 O:O′-bis[(1,10-phenanthroline-κ2 N,N′)(2-phenoxypropionato-κ2 O,O′)praseodymium(III)]
In the centrosymmetric binuclear title complex, [Pr2(C9H9O3)6(C12H8N2)2], the two PrIII ions are linked by four 2-phenoxypropionate (L) groups through their bi- and tridentate bridging modes. Each PrIII ion is nine-coordinated by one 1,10-phenanthroline molecule, one bidentate carboxylate group and four bridging carboxylate groups in a distorted PrN2O7 monocapped square-antiprismatic geometry. The title compound is isotypic with its terbium- and dysprosium-containing analogues
Tetrakis(μ2-2-phenoxypropionato)-κ3 O,O′:O′;κ3 O:O,O′;κ4 O:O′-bis[(1,10-phenanthroline-κ2 N,N′)(2-phenoxypropionato-κ2 O,O′)lanthanum(III)]
In the centrosymmetric binuclear title complex, [La2(C9H9O3)6(C12H8N2)2], the two La(III) ions are linked by four 2-phenoxypropionate (L) groups in bi- and tridentate bridging modes. Each LaIII ion is nine-coordinated by one 1,10-phenanthroline molecule, one bidentate chelating carboxylate group and four bridging carboxylate groups in a distorted LaN2O7 monocapped square-antiprismatic geometry
Bis(μ2-2-phenoxypropionato-κ2 O:O′)bis[(1,10-phenanthroline-κ2 N,N′)bis(2-phenoxypropionato-κ2 O,O′)ytterbium(III)]
In the centrosymmetric binuclear title complex, [Yb2(C9H9O3)6(C12H8N2)2], the two Yb(III) ions are linked by two 2-phenoxypropionate (L) groups in a bidentate bridging mode. Each YbIII ion is eight-coordinated by two O atoms from two bridging L ligands, four O atoms from two chelating L groups and two N atoms from one chelating phen molecule in a distorted YbN2O6 dodecahedral geometry
Tetrakis(μ-2-phenoxypropionato)-κ3 O,O′:O′;κ3 O:O,O′,κ4 O:O′-bis[(1,10-phenanthroline-κ2 N,N′)(2-phenoxypropionato-κ2 O,O′)dysprosium(III)]
In the centrosymmetric binuclear title complex, [Dy2(C9H9O3)6(C12H8N2)2], the two DyIII ions are linked by four 2-phenoxypropionate (L) groups through their bi- and tridentate bridging modes. Each DyIII ion is nine-coordinated by one 1,10-phenanthroline molecule, one bidentate carboxylate group and four bridging carboxylate groups in a distorted DyN2O7 monocapped square-antiprismatic geometry. The title compound is isotypic with its terbium-containing analogue
Structure of human tryptophanyl-tRNA synthetase in complex with tRNA(Trp) reveals the molecular basis of tRNA recognition and specificity
Aminoacyl-tRNA synthetases (aaRSs) are a family of enzymes responsible for the covalent link of amino acids to their cognate tRNAs. The selectivity and species-specificity in the recognitions of both amino acid and tRNA by aaRSs play a vital role in maintaining the fidelity of protein synthesis. We report here the first crystal structure of human tryptophanyl-tRNA synthetase (hTrpRS) in complex with tRNA(Trp) and Trp which, together with biochemical data, reveals the molecular basis of a novel tRNA binding and recognition mechanism. hTrpRS recognizes the tRNA acceptor arm from the major groove; however, the 3′ end CCA of the tRNA makes a sharp turn to bind at the active site with a deformed conformation. The discriminator base A73 is specifically recognized by an α-helix of the unique N-terminal domain and the anticodon loop by an α-helix insertion of the C-terminal domain. The N-terminal domain appears to be involved in Trp activation, but not essential for tRNA binding and acylation. Structural and sequence comparisons suggest that this novel tRNA binding and recognition mechanism is very likely shared by other archaeal and eukaryotic TrpRSs, but not by bacterial TrpRSs. Our findings provide insights into the molecular basis of tRNA specificity and species-specificity
Triaquabis{2-methoxy-6-[(phenyliminiumyl)methyl]phenolate-κO 1}manganese(II) dinitrate
The crystal structure of the title compound, [Mn(C14H13NO2)2(H2O)3](NO3)2, is comprised of two Schiff base 2-methoxy-6-(N-phenylcarboximidoyl)phenol (HL) ligands and three coordinated water molecules. The MnII ion lies on a twofold axis that bisects one water O atom. The coordination sphere of the five-coordinate Mn atom is completed by the two monodentate HL ligands and three coordinated water molecules binding through their O atoms, affording a distorted tetragonal–pyramidal geometry. In the phenolate ligands, the hydroxy H atom transfers to the imine N atom. This H atom is also involved in an intramolecular N—H⋯O hydrogen bond that imposes a nearly planar conformation on each ligand, with dihedral angles of 2.78 (3) and 2.43 (5)° between the aromatic rings of each ligand. In the crystal, molecules are linked by intermolecular O—H⋯O hydrogen bonds
Tris{2-methoxy-6-[(4-methylphenyl)iminiomethyl]phenolate-κ2 O,O′}tris(thiocyanato-κN)lanthanum(III)
In the title compound, [La(NCS)3(C15H15NO2)3], the metal centre is nine-coordinated by six O atoms from three zwitterionic Schiff base 2-methoxy-6-[(4-methylphenyl)iminiomethyl]phenolate (L) ligands and three terminal N atoms of the thiocyanate ions in a monocapped square-antiprismatic environment. The L ligands chelate the LaIII ion with strong La—O(deprotonated phenolic) bonds [2.435 (3)–2.464 (3) Å] and significantly longer La—O(methoxy) bonds [2.801 (3)–2.831 (3) Å]. The La—N bond lengths range from 2.541 (4) to 2.605 (4) Å
catena-Poly[[[bis(3-hydroxyadamantane-1-carboxylato-κO 1)(3-hydroxyadamantane-1-carboxylic acid-κO 1)zinc(II)]-μ2-4,4′-bipyridine] monohydrate]
In the title coordination polymer, {[Zn(C11H15O3)2(C10H8N2)(C11H16O3)]·H2O}n, the ZnII ion is five coordinated by two N atoms from two 4,4′-bipyridine (4,4′-bpy) molecules and three O atoms from two 3-hydroxyadamantane-1-carboxylate anions (L) and one 3-hydroxyadamantane-1-carboxylic acid (HL) molecule. The resulting coordination polyhedron is a near regular ZnN2O3 trigonal bipyramid, with the N atoms in axial sites. The 4,4′-bpy molecules [dihedral angle between the aromatic rings = 17.2 (2)°] act as bridges, connecting the metal ions into an infinite polymeric chain propagating in [01]. O—H⋯O hydrogen bonds help to consolidate the packing
2-Phenyl-1,3-selenazole-4-carboxylic acid
In the title compound, C10H7NO2Se, the two rings are twisted, making a dihedral angle of 12.42 (9)°. In the crystal, pairs of molecules are disposed about an inversion center, generating O—H⋯O hydrogen-bonded dimers
Tris(1,10-phenanthroline-κ2 N,N′)zinc(II) chloride 2-phenyl-4-selenazole-5-carboxylate decahydrate
The asymmetric unit of the title salt, [Zn(C12H8N2)3](C10H6NO2Se)Cl·10H2O, contains a [Zn(phen)3]2+ cation (phen is 1,10-phenanthroline), uncoordinated chloride and 2-phenyl-4-selenazole-5-carboxylate anions and ten uncoordinated water molecules. The central ZnII ion is six-coordinated by six N atoms from three phen ligands in a distorted octahedral geometry. An extensive O—H⋯O, O—H⋯N and O—H⋯Cl hydrogen-bonding network stabilizes the crystal structure
- …