Thyroid Hormone Stereochemistry. II. Molecular Structure of Thyronine HCl Ethyl Ester Monohydrate

1974 ◽  
Vol 52 (17) ◽  
pp. 3042-3047 ◽  
Author(s):  
Arthur Camerman ◽  
Norman Camerman
Keyword(s):  
Ethyl Ester ◽  
Three Dimensional ◽  
Chloride Ion ◽  
Dimensional Structure ◽  
Side Chain ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Ether Linkage ◽  
Cell Dimensions ◽  
Phenyl Rings

The three-dimensional structure of L-thyronine, the non-iodinated physiologically inactive analog of thyroxine, has been determined by single crystal X-ray diffraction and compared to the active thyroid hormones. The compound crystallized as the monohydrate of thyronine hydrochloride ethyl ester in the monoclinic space group P21 with cell dimensions a = 10.502, b = 5.165, c = 17.940 Å, β = 109.74°. The structure was solved by Patterson methods to find the chloride ion and iterative Fourier maps to locate the rest of the atoms. Refinement was by anisotropic full-matrix least squares to convergence at R = 0.048.The two phenyl rings adopt a twisted orientation with respect to each other with angles of −37° and −67° between the plane of the inter-ring ether linkage and the planes of the α- and β-rings, respectively. This orientation differs considerably from that found in the iodinated thyronines. The conformation of the alanine side chain is remarkably similar to that of the alanine in the iodinated thyronines.

Thyroid Hormone Stereochemistry. III. Molecular Structure of Triiodothyropropionic Acid Ethyl Ester

1974 ◽  
Vol 52 (17) ◽  
pp. 3048-3053 ◽  
Author(s):  
Norman Camerman ◽  
Arthur Camerman
Keyword(s):  
Ethyl Ester ◽  
Iodine Atom ◽  
Molecular Conformation ◽  
Three Dimensional ◽  
Acid Ethyl Ester ◽  
Dimensional Structure ◽  
Monoclinic Space Group ◽  
Ether Linkage ◽  
Cell Dimensions ◽  
Phenyl Rings

The three-dimensional structure of triiodothyropropionic acid ethyl ester has been determined as part of an investigation of the stereochemistry of the thyroid hormones. The compound crystallizes in the monoclinic space group P21/c, with cell dimensions a = 14.60, b = 8.843, c = 16.70 Å, β = 111°27′; Z = four molecules per cell. The structure was determined by direct centrosymmetric phasing procedures to locate the iodine atoms and phasing on the iodines to find the light atoms. Refinement was by anisotropic full-matrix least squares to a final discrepancy value R = 0.038.The two phenyl rings in the molecule are skewed with respect to each other and are not far from being mutually perpendicular, with angles of 88 and 10° between the plane of the inter-ring ether linkage and the planes of the diiodo-ring and the monoiodo-ring, respectively. The conformation is such that the 3′-iodine atom is proximal to the diiodo-ring, similar to the molecular conformation found in the crystal structure of triiodo-L-thyronine hydrochloride.

Structure and conformation of the anticodon nucleoside 5-methoxyuridine in the solid state and in solution

1983 ◽  
Vol 61 (10) ◽  
pp. 2299-2304 ◽  
Author(s):  
George I. Birnbaum ◽  
Wayne J. P. Blonski ◽  
Frank E. Hruska
Keyword(s):  
Solid State ◽  
Three Dimensional ◽  
Direct Methods ◽  
Pyrimidine Ring ◽  
Dimensional Structure ◽  
Side Chain ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Cell Dimensions ◽  
Enol Tautomer

The three-dimensional structure of 5-methoxyuridine (mo5U) was determined with much higher precision than in a previous study (Hillen etal. J. Carbohydr. Nucleosides Nucleotides, 5, 23 (1978)). The crystals belong to the monoclinic space group P21 and the cell dimensions are a = 8.916(2), b = 14.372(2), c = 4.714(1) Å, β = 97.44(2)°. Intensity data were measured with a diffractometer and the structure was solved by direct methods. Least-squares refinement, which included all hydrogen atoms, converged at R = 0.031. The conformation about the glycosyl bond is anti (χCN = 23.1°), the pucker of the ribose ring is C(3′)endo, and the conformation of the —CH2OH side chain is gauche+. A comparison of the bond lengths N(3)—C(4) and C(4)—O(4) with those in uridine does not support the conclusion of Hillen etal. about a shift to the enol tautomer in mo5U. However, there are other changes in the geometry of the pyrimidine ring due to substitution at C(5). A conformational analysis, based on 1H and 13C nmr data, shows that the preferred conformation in solution is that observed in the solid state.

Structure and conformation of the hydrochloride of pseudoisocytidine, an antileukemic C-nucleoside

1980 ◽  
Vol 58 (16) ◽  
pp. 1633-1638 ◽  
Author(s):  
George I. Birnabaum ◽  
Kyoichi A. Watanabe ◽  
Jack J. Fox
Keyword(s):  
Heavy Atom ◽  
Three Dimensional ◽  
Direct Methods ◽  
Dimensional Structure ◽  
Side Chain ◽  
Hydrogen Atoms ◽  
Triclinic Space Group ◽  
X Ray Crystallography ◽  
Cell Dimensions ◽  
Sugar Ring

The three-dimensional structure of pseudoisocytidine hydrochloride was determined by X-ray crystallography. The crystals belong to the triclinic space group P1 and the cell dimensions are a = 6.623(2), b = 8.053(2), c = 6.201(2) Å, α = 108.35(2), β = 101.36(2), γ = 93.54(2) °. Intensity data were measured with a diffractometer and the structure was solved by a combination of heavy-atom and direct methods. Least-squares refinement, which included hydrogen atoms, converged at R = 0.040. The conformation about the glycosyl bond is anti (χCC = 21.6°), the pucker of the furanose ring is C(1′)exo, and the conformation of the —CH2OH side chain is gauche–trans (t). An examination of bond lengths indicates that of the three main resonance forms of the isocytosine cation the fully conjugated one contributes more to the structure than the cross-conjugated one. Bond angles in the sugar ring reflect its rare conformation.

Preparation and structure of mer-trichloro(acetonitrile)bis-(triphenylphosphine)osmium(III)

1980 ◽  
Vol 58 (10) ◽  
pp. 1042-1045 ◽  
Author(s):  
R. L. Parkes ◽  
N. C. Payne ◽  
E. O. Sherman
Keyword(s):  
Three Dimensional ◽  
Phosphine Ligands ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Distorted Octahedral Coordination Geometry ◽  
Distorted Octahedral ◽  
Cell Dimensions ◽  
The Mean ◽  
Bond Trans

An air-stable, red, crystalline, N-bonded acetonitrile complex of Os(III), OsCl3(NCCH3)(P(C6H5)3)2, has been prepared and characterized by elemental analysis, magnetic susceptibility, and a single crystal X-ray structure determination. Crystals are monoclinic, space group P21/c, cell dimensions a = 10.029(2), b = 15.233(2), c = 25.246(4) Å, β = 113.65(1)°, and Z = 4. Three dimensional X-ray diffraction intensity data were collected on an automatic four circle diffractometer using Cu radiation. Full-matrix least-squares refinement on F converged at R = 0.038 for 4384 unique observations. The Os atom has a slightly distorted octahedral coordination geometry, with trans phosphine ligands, mean Os—P 2.406(2) Å. The acetonitrile ligand is σ-bonded through the N atom, Os—N 2.038(6) Å. The bond trans to the acetonitrile ligand. Os—Cl(1) 2.364(2) Å, is not significantly different from the mean of the cisOs—Cl bonds, 2.361(2) Å.

scholarly journals Crystallization and preliminary X-ray diffraction studies of La1 fromLiocheles australasiae

2014 ◽  
Vol 70 (7) ◽  
pp. 915-917 ◽  
Author(s):  
Saori Kamachi ◽  
Junya Nagao ◽  
Masahiro Miyashita ◽  
Yoshiaki Nakagawa ◽  
Hisashi Miyagawa ◽  
...  
Keyword(s):  
Biological Function ◽  
Three Dimensional ◽  
Scorpion Venom ◽  
Dimensional Structure ◽  
Diffusion Method ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Cell Parameters ◽  
Factor Type ◽  
Von Willebrand

A novel scorpion venom peptide, La1 fromLiocheles australasiae, with a molecular weight of 7.8 kDa, is presumed to possess a single von Willebrand factor type C (VWC) domain, a common protein module, based on the position of eight Cys residues in its sequence. The biological function of La1 is still unknown. Deciphering its three-dimensional structure will be helpful in understanding its biological function. La1 was crystallized by the sitting-drop vapour-diffusion method using magnesium sulfate as a precipitant. The crystals belonged to the monoclinic space groupC2, with unit-cell parametersa= 63.0,b= 30.2,c= 32.3 Å, β = 108.5°, and diffracted to 1.9 Å resolution. The calculatedVMbased on one molecule per asymmetric unit was 1.87 Å3 Da−1. The solvent content was 34.1%.

One- and two-dimensional CdIIcoordination polymers incorporating organophosphinate ligands

2014 ◽  
Vol 70 (11) ◽  
pp. 1069-1074 ◽  
Author(s):  
Jeffrey A. Rood ◽  
Steven Boyer ◽  
Allen G. Oliver
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Cadmium Nitrate ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
Phenyl Rings ◽  
Ft Ir ◽  
Ir Analysis ◽  
The One

Reaction of cadmium nitrate with diphenylphosphinic acid in dimethylformamide solvent yielded the one-dimensional coordination polymercatena-poly[[bis(dimethylformamide-κO)cadmium(II)]-bis(μ-diphenylphosphinato-κ2O:O′)], [Cd(C12H10O2P)2(C3H7NO)2]n, (I). Addition of 4,4′-bipyridine to the synthesis afforded a two-dimensional extended structure, poly[[(μ-4,4′-bipyridine-κ2N:N′)bis(μ-diphenylphosphinato-κ2O:O′)cadmium(II)] dimethylformamide monosolvate], {[Cd(C12H10O2P)2(C10H8N2)]·C3H7NO}n, (II). In (II), the 4,4′-bipyridine molecules link the CdIIcenters in the crystallographicadirection, while the phosphinate ligands link the CdIIcenters in the crystallographicbdirection to complete a two-dimensional sheet structure. Consideration of additional π–π interactions of the phenyl rings in (II) produces a three-dimensional structure with channels that encapsulate dimethylformamide molecules as solvent of crystallization. Both compounds were characterized by single-crystal X-ray diffraction and FT–IR analysis.

scholarly journals Three-Dimensional Structure of Cytochrome c Nitrite Reductase As Determined by Cryo-Electron Microscopy

Acta Naturae ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 48-56 ◽  
Author(s):  
T. N. Baymukhametov ◽  
Yu. M. Chesnokov ◽  
E. B. Pichkur ◽  
K. M. Boyko ◽  
T. V. Tikhonova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cytochrome C ◽  
Nitrite Reductase ◽  
Three Dimensional ◽  
Structural Heterogeneity ◽  
Dimensional Structure ◽  
Side Chain ◽  
X Ray Diffraction ◽  
Cytochrome C Nitrite Reductase ◽  
Cryo Electron Microscopy

The structure of cytochrome c nitrite reductase from the bacterium Thioalkalivibrio nitratireducens was determined by cryo-electron microscopy (cryo-EM) at a 2.56 resolution. Possible structural heterogeneity of the enzyme was assessed. The backbone and side-chain orientations in the cryo-EM-based model are, in general, similar to those in the high-resolution X-ray diffraction structure of this enzyme.

Captopril and its dimer captopril disulfide: comparative structural and conformational studies

2015 ◽  
Vol 71 (3) ◽  
pp. 199-203 ◽  
Author(s):  
Joanna Bojarska ◽  
Waldemar Maniukiewicz ◽  
Andrzej Fruziński ◽  
Lesław Sieroń ◽  
Milan Remko
Keyword(s):  
Minimum Energy ◽  
Three Dimensional ◽  
Sulfhydryl Group ◽  
Conformational Search ◽  
Side Chain ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

The crystal structures of captopril {systematic name: (2S)-1-[(2S)-2-methyl-3-sulfanylpropanoyl]pyrrolidine-2-carboxylic acid}, C9H15NO3S, (1), and its dimer disulfide metabolite, 1,1′-{disulfanediylbis[(2S)-2-methyl-1-oxopropane-3,1-diyl]}bis-L-proline, C18H28N2O6S2, (2), were determined by single-crystal X-ray diffraction analysis. Compound (1) crystallizes in the orthorhombic space groupP212121, while compound (2) crystallizes in the monoclinic space groupP21, both with one molecule per asymmetric unit. The molecular geometries of (1) and (2) are quite similar, but certain differences appear in the conformations of the five-membered proline rings and the side chains containing the sulfhydryl group. The proline ring adopts an envelope conformation in (1), while in (2) it exists in envelope and slightly deformed half-chair conformations. The conformation adopted by the side chain is extended in (1) and folded in (2). A minimum-energy conformational search using Monte Carlo methods in the aqueous phase reveals that the optimized conformations of the title compounds differ from those determined crystallographically, which depend on their immediate environment. Intermolecular O—H...O and relatively weak C—H...O interactions seem to be effective in both structures and, together with S—H...O and C—H...S contacts, they create three-dimensional networks.

Electron Microscopy of Cytoplasmic Contractile Proteins

1978 ◽  
Vol 36 (3) ◽  
pp. 606-614 ◽  
Author(s):  
T.D. Pollard ◽  
P. Maupin
Keyword(s):  
Electron Microscopy ◽  
Actin Filaments ◽  
Three Dimensional ◽  
Uranyl Acetate ◽  
Contractile Proteins ◽  
Dimensional Structure ◽  
X Ray Diffraction ◽  
Cytoplasmic Matrix ◽  
Computer Image Processing ◽  
Nonmuscle Cells

In this paper we review some of the contributions that electron microscopy has made to the analysis of actin and myosin from nonmuscle cells. We place particular emphasis upon the limitations of the ultrastructural techniques used to study these cytoplasmic contractile proteins, because it is not widely recognized how difficult it is to preserve these elements of the cytoplasmic matrix for electron microscopy. The structure of actin filaments is well preserved for electron microscope observation by negative staining with uranyl acetate (Figure 1). In fact, to a resolution of about 3nm the three-dimensional structure of actin filaments determined by computer image processing of electron micrographs of negatively stained specimens (Moore et al., 1970) is indistinguishable from the structure revealed by X-ray diffraction of living muscle.

A New POM-Based Supramolecular Compound: Synthesis, Structure and Adsorptive Property of [Cu(phen)2]3[W6O19]

2014 ◽  
Vol 919-921 ◽  
pp. 2013-2016 ◽  
Author(s):  
Ya Bing Liu ◽  
Hong Jie Wang ◽  
Hong Kai Zhao
Keyword(s):  
Three Dimensional ◽  
Building Blocks ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Hybrid Compound ◽  
Adsorptive Property ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Compound Synthesis ◽  
Metal Organic

A POM - based organice - inorganic hybrid compound with the chemical formula of[Cu (phen)2]3[W6O19] (phen = 1,10-phenanthroline) (1) has been hydrothermally synthesized andstructurally characterized by the elemental analysis, and single crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic space groupC2/c witha=18.319(4) Å,b= 17.311(4) Å,c= 22.248(4) Å,β= 112.40(3) o,V= 6523(2) Å3,Z= 4, R1= 0.0448, andwR2=0.1218. Compound 1 consists of the [W6O19]3-building blocks and [Cu (phen)2]+metal organic cationic moieties, which are packed together via the extensive hydrogen-bonding interactions to form a three-dimensional supramolecular framework. The adsorption of methylene blue (MB) under UV irradiation with 1 as the heterogeneous adsorbent has been investigated, showing a good adsorptive property of 1 for MB degradation.

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