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Three-dimensional Crystal Structure (three-dimensional + crystal_structure)

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Chemistry100%

Selected Abstracts

{4-[(Carbamimidoylhydrazono)methyl-,2N1,N4]-5-hydroxymethyl-2-methylpyridinium-3-olate-,O}(methanol-,O)copper(II) dinitrate

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2009
Vukadin M. Leovac
The title compound, [Cu(C9H13N5O2)(CH4O)](NO3)2, consists of square-planar cationic complex units where the CuII centre is coordinated by an N,N,,O -tridentate pyridoxal,aminoguanidine Schiff base adduct and a methanol molecule. The tridentate ligand is a zwitterion exhibiting an almost planar conformation. The dihedral angles between the mean planes of the pyridoxal ring and the six- and five-membered chelate rings are all less than 2.0°. The charge on the complex cation is neutralized by two nitrate counter-ions. Extensive N,H...O and C,H...O hydrogen bonding connects these ionic species and leads to the formation of layers. The pyridoxal hydroxy groups are the only fragments that deviate significantly from the flat layer structure; these groups are involved in O,H...O hydrogen bonding, connecting the layers into a three-dimensional crystal structure. [source]

catena -Poly­[[dicyan­amido(1,10-phen­anthroline)copper(II)]-,-dicyan­amido]

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2000
Zhe-Ming Wang
The title compound, [Cu(C2N3)2(C12H8N2)]n, has a sheet-like structure, built by [Cu(phen)(dca)2]n (phen is 1,10-phenanthroline and dca is dicyan­amide) chains which are interconnected by secondary long Cu,N bonds between the chains. The Cu2+ ion is in a distorted tetragonal bipyramidal (5,+,1) coordination environment. The sheets stack into the three-dimensional crystal structure through aromatic interactions between the coordinated phen ligands of adjacent sheets. [source]

Free and ATP-bound structures of Ap4A hydrolase from Aquifex aeolicus V5

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2010
Jeyaraman Jeyakanthan
Asymmetric diadenosine tetraphosphate (Ap4A) hydrolases degrade the metabolite Ap4A back into ATP and AMP. The three-dimensional crystal structure of Ap4A hydrolase (16,kDa) from Aquifex aeolicus has been determined in free and ATP-bound forms at 1.8 and 1.95,Å resolution, respectively. The overall three-dimensional crystal structure of the enzyme shows an ,,,-sandwich architecture with a characteristic loop adjacent to the catalytic site of the protein molecule. The ATP molecule is bound in the primary active site and the adenine moiety of the nucleotide binds in a ring-stacking arrangement equivalent to that observed in the X-ray structure of Ap4A hydrolase from Caenorhabditis elegans. Binding of ATP in the active site induces local conformational changes which may have important implications in the mechanism of substrate recognition in this class of enzymes. Furthermore, two invariant water molecules have been identified and their possible structural and/or functional roles are discussed. In addition, modelling of the substrate molecule at the primary active site of the enzyme suggests a possible path for entry and/or exit of the substrate and/or product molecule. [source]

Structure of cyclophilin from Leishmania donovani bound to cyclosporin at 2.6,Å resolution: correlation between structure and thermodynamic data

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 11 2009
Vandavasi Venugopal
Drug development against Leishmania donovani, the pathogen that causes visceral leishmaniasis in humans, is currently an active area of research given the widespread prevalence of the disease and the emergence of resistant strains. The immunosuppressive drug cyclosporin is known to have antiparasitic activity against a variety of pathogens. The receptor for cyclosporin is the protein cyclophilin, which is a ubiquitous peptidylprolyl isomerase. The crystal structure of cyclophilin from L. donovani complexed with cyclosporin has been solved at 2.6,Å resolution. The thermodynamic parameters of the interaction have been determined using spectroscopic and calorimetric techniques. A detailed effort has been made to predict the thermodynamic parameters of binding from computations based on the three-dimensional crystal structure. These results were in good agreement with the corresponding experimental values. Furthermore, the structural and biophysical results have been discussed in the context of leishmanial drug resistance and could also set the stage for the design of potent non-immunosuppressive antileishmanials. [source]