Crystallographic Characterization (crystallographic + characterization)

Distribution by Scientific Domains
Distribution within Chemistry

Kinds of Crystallographic Characterization

  • preliminary crystallographic characterization


  • Selected Abstracts


    Preparation, Crystallographic Characterization, and Theoretical Study of C70(CF3)14,

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 11 2006
    Alexey A. Goryunkov
    Abstract Five C70(CF3)14 isomers have been isolated chromatographically from the mixture produced in the ampoule reaction between C70 and CF3I at 390 C. Molecular structures of four isomers have been determined in a single-crystal X-ray diffraction study. A quantum chemical survey of the theoretically possible isomers demonstrated that the structures obtained are energetically favorable but that there is probably no full thermodynamic control in the trifluoromethylation process.( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]


    Preparation, Crystallographic Characterization and Theoretical Study of Two Isomers of C70(CF3)12.

    CHEMINFORM, Issue 34 2006
    Daria V. Ignat'eva
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]


    Probing, Inhibition, and Crystallographic Characterization of Metallo-,-lactamase (IMP-1) with Fluorescent Agents Containing Dansyl and Thiol Groups

    CHEMMEDCHEM, Issue 9 2006
    Hiromasa Kurosaki Dr.
    A series of fluorescent probes, N -(5-(dimethylamino)-1-naphthalenesulfonamido(alkyl)n)-3-thiopropionamide (DansylCnSHs), were rationally designed to detect and inhibit metallo-,-lactamase (IMP-1). These compounds were shown to function as fluorescent probes for and inhibitors of metallo-,-lactamases. The X-ray crystallographic structure shown indicates the potential of these agents for use as a new fluorescent probes for metallo-,-lactamases. [source]


    Crystallographic characterization of the first reported crystalline form of the potent hallucinogen (R)-2-amino-1-(8-bromobenzo[1,2- b;5,4- b,]difuran-4-yl)propane or `bromodragonfly': the 1:1 anhydrous proton-transfer compound with 3,5-dinitrosalicylic acid

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2010
    Graham Smith
    The 1:1 proton-transfer compound of the potent substituted amphetamine hallucinogen (R)-2-amino-1-(8-bromobenzo[1,2- b;5,4- b,]difuran-4-yl)propane (common trivial name `bromodragonfly') with 3,5-dinitrosalicylic acid, namely 1-(8-bromobenzo[1,2- b;5,4- b,]difuran-4-yl)propan-2-aminium 2-carboxy-4,6-dinitrophenolate, C13H13BrNO2+C7H3N2O7,, forms hydrogen-bonded cation,anion chain substructures comprising undulating head-to-tail anion chains formed through C(8) carboxyl,nitro O,H...O associations and incorporating the aminium groups of the cations. The intrachain cation,anion hydrogen-bonding associations feature proximal cyclic R33(8) interactions involving both an N+,H...Ophenolate and the carboxyl,nitro O,H...O associations and aromatic ,,, ring interactions [minimum ring centroid separation = 3.566,(2),]. A lateral hydrogen-bonding interaction between the third aminium H atom and a carboxyl O-atom acceptor links the chain substructures, giving a two-dimensional sheet structure. This determination represents the first of any form of this compound and is in the (R) absolute configuration. The atypical crystal stability is attributed both to the hydrogen-bonded chain substructures provided by the anions, which accommodate the aminium proton-donor groups of the cations and give crosslinking, and to the presence of the cation,anion aromatic ring ,,, interactions. [source]


    Crystallographic characterization of the radixin FERM domain bound to the cytoplasmic tail of the adhesion protein ICAM-2

    ACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2001
    Keisuke Hamada
    Radixin is a member of the ERM proteins, which cross-link plasma membranes and actin filaments. The FERM domains located at the N-terminal regions of ERM proteins are responsible for membrane association through direct interactions with the cytoplasmic domains of integral membrane proteins. Here, crystals of the complex between the radixin FERM domain and the full-length cytoplasmic tail (28-residue peptide) of intercellular adhesion molecule 2, ICAM-2, have been obtained. The crystals were found to belong to space group P3121 or P3221, with unit-cell parameters a = b = 100.44,(9), c = 99.49,(6),, and contain one complex in the crystallographic asymmetric unit. An intensity data set was collected to a resolution of 2.60,. [source]


    Crystallographic characterization of the PDZ1 domain of the human Na+/H+ exchanger regulatory factor

    ACTA CRYSTALLOGRAPHICA SECTION D, Issue 5 2001
    Gordon Webster
    The Na+/H+ exchanger regulatory factor (NHERF) contains two PDZ domains that mediate the assembly of transmembrane and cytosolic proteins into functional signal transduction complexes. The human NHERF PDZ1 domain, which spans residues 11,99, interacts specifically with carboxy-terminal residues of the ,2 adrenergic receptor and the cystic fibrosis transmembrane conductance regulator. The NHERF PDZ1 was expressed in Escherichia coli as a soluble protein, purified and crystallized in the unbound form using the vapor-diffusion method with 2,M ammonium sulfate as the precipitant. Diffraction data were collected to 1.5, resolution using synchrotron radiation. The crystals belong to space group P3121 or P3221, with unit-cell parameters a = b = 51.6, c = 58.9,, and one molecule in the asymmetric unit. [source]


    Crystallographic characterization of the passenger domain of the Bordetella autotransporter BrkA

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2009
    Li Zhao
    Autotransporters (ATs) are proteins that deliver effectors (the passenger domain) to the surface of Gram-negative bacteria by the type V secretion pathway. The passenger domain of BrkA, a Bordetella pertussis autotransporter mediating serum resistance and adherence, was cloned in a pET expression system and overexpressed in Escherichia coli. The gene product was correctly refolded, purified to homogeneity and crystallized. The crystals diffracted to 2.8, resolution. The space group was assumed to be P41212, with unit-cell parameters a = b = 108.19, c = 115.35,. [source]


    Crystallographic characterization of a multidomain histidine protein kinase from an essential two-component regulatory system

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2009
    Haiyan Zhao
    YycGF is a highly conserved two-component signal transduction system that is specific to low-G+C Gram-positive bacteria, including many important human pathogens. It has been recognized as a crucial regulatory system for cell-wall metabolism. YycG, the histidine protein kinase of this system, is a multidomain transmembrane protein. The truncated cytoplasmic portion of YycG from Bacillus subtilis encompassing the PAS domain, the dimerization domain and the catalytic domain was expressed, purified and crystallized. X-ray data were collected to 2.8, resolution with a completeness of 98.2% and an overall Rmerge of 5.6%. The crystals belonged to space group P61 or P65, with unit-cell parameters a = 135.0, c = 133.0,. The selenomethionine-substituted version of the protein was crystallized and X-ray data were collected to 3.6, resolution for subsequent MAD phasing. [source]


    Crystallographic characterization of the N-terminal domain of a plant NADPH oxidase

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2008
    Takashi Oda
    Respiratory burst oxidase homologue (Rboh), which is found in the plasma membrane, is a generator of reactive oxygen species (ROS) in plants. Many studies have indicated that the ROS produced by Rboh play critical roles in various cellular activities, including plant defence against pathogens. Crystals of the N-terminal domain of Oryza sativa RbohB (OsRbohB) have been obtained. The crystals belonged to space group P212121, with unit-cell parameters a = 60.4, b = 72.2, c = 118.9,. An intensity data set was collected to 2.4, resolution. [source]


    Crystallographic characterization of the radixin FERM domain bound to the cytoplasmic tails of adhesion molecules CD43 and PSGL-1

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 1 2007
    Yumiko Takai
    Radixin is a member of the ERM proteins that cross-link plasma membranes and actin filaments. The FERM domains located in the N-terminal regions of ERM proteins are responsible for membrane association through direct interaction with the cytoplasmic tails of integral membrane proteins. Here, crystals of the radixin FERM domain bound to the cytoplasmic peptides of two adhesion molecules, CD43 and PSGL-1, have been obtained. Crystals of the radixin FERM domain bound to CD43 belong to space group P4322, with unit-cell parameters a = b = 68.72, c = 201.39,, and contain one complex in the crystallographic asymmetric unit. Crystals of the radixin FERM domain bound to PSGL-1 belong to space group P212121, with unit-cell parameters a = 80.74, b = 85.73, c = 117.75,, and contain two complexes in the crystallographic asymmetric unit. Intensity data sets were collected to a resolution of 2.9, for the FERM,CD43 complex and 2.8, for the FERM,PSGL-1 complex. [source]


    MAGNESIUM-RICH INTRALENSAR STRUCTURES IN SCHIZOCHROAL TRILOBITE EYES

    PALAEONTOLOGY, Issue 5 2007
    MARTIN R. LEE
    Abstract:, The interpretation of the lenses of schizochroal trilobite eyes as aplanatic doublets by Clarkson and Levi-Setti over 30 years ago has been widely accepted. However, the means of achieving a difference in refractive index across the interface between the two parts of each lens to overcome spherical aberration has remained a matter of speculation and lately it has been argued that the doublet structure itself is no more than a diagenetic artefact. Recent advances in technologies for imaging, chemical analysis and crystallographic characterization of minerals at high spatial resolutions have enabled a re-examination of the structure of calcite lenses at an unprecedented level of detail. The lenses in the eyes of the specimen of Dalmanites sp. used in the original formulation of the aplanatic doublet hypothesis are shown to have undergone diagenetic alteration, but its products reflect original differences in mineral chemistry between the upper lens unit and lower intralensar bowl. The turbidity of the bowl and of the core within the upper part of the lens are the result of their greater microporosity and abundance of microdolomite inclusions, both of which were products of diagenetic replacement of original magnesian calcite in these areas. Such a difference in magnesium concentration in the original calcite has long been postulated as one of the ways by which the interface between these lens units could have produced an aberration-free image and the present study provides the first direct evidence of such a chemical contrast, thus confirming the doublet hypothesis. [source]


    Introduction to a general crystallography

    ACTA CRYSTALLOGRAPHICA SECTION A, Issue 4 2001
    A. Janner
    The definition of an extended crystallographic group is given, based on an -dimensional Euclidean space, carrier of a faithful integral representation of a permutation group of atomic positions. The Euclidean crystallography of normal crystals and the higher-dimensional one applied to incommensurately modulated crystals, intergrowth crystals and quasicrystals are special cases of a general crystallography. The same is true for the multimetrical crystallographic characterization of ice and of snow crystals. This approach can also be applied to single molecules, leading to what may be denoted as molecular crystallography. It possibly allows non-trivial structural relations between atomic positions belonging to the asymmetric unit of the molecular point group to be obtained. Two simple molecules, polycyclic aromatic hydrocarbons, are treated as illustrative examples. [source]


    Hydrogen bonding and ,,, interactions in 1-benzofuran-2,3-dicarboxylic acid and its 1:1 cocrystals with pyridine, phenazine and 1,4-phenylenediamine

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009
    Hatem M. Titi
    The structure of 1-benzofuran-2,3-dicarboxylic acid (BFDC), C10H6O5, (I), exhibits an intramolecular hydrogen bond between one ,COOH group and the other, while the second carboxyl function is involved in intermolecular hydrogen bonding to neighbouring species. The latter results in the formation of flat one-dimensional hydrogen-bonded chains in the crystal structure, which are ,,, stacked along the normal to the plane of the molecular framework, forming a layered structure. 1:1 Cocrystallization of BFDC with pyridine, phenazine and 1,4-phenylenediamine is associated with H-atom transfer from BFDC to the base and charge-assisted hydrogen bonding between the BFDC, monoanion and the corresponding ammonium species, while preserving, in all cases, the intramolecular hydrogen bond between the carboxyl and carboxylate functions. The pyridinium 2-carboxylato-1-benzofuran-3-carboxylic acid, C5H6N+C10H5O5,, (II), and phenazinium 3-carboxylato-1-benzofuran-2-carboxylic acid, C12H9N2+C10H5O5,, (III), adducts form discrete hydrogen-bonded ion-pair entities. In the corresponding crystal structures, the two components are arranged in either segregated or mixed ,,, stacks, respectively. On the other hand, the structure of 4-aminoanilinium 2-carboxylato-1-benzofuran-3-carboxylic acid, C6H9N2+C10H5O5,, (IV), exhibits an intermolecular hydrogen-bonding network with three-dimensional connectivity. Moreover, this fourth structure exhibits induction of supramolecular chirality by the extended hydrogen bonding, leading to a helical arrangement of the interacting moieties around 21 screw axes. The significance of this study is that it presents the first crystallographic characterization of pure BFDC, and manifestation of its cocrystallization with a variety of weakly basic amine molecules. It confirms the tendency of BFDC to preserve its intramolecular hydrogen bond and to prefer a monoanionic form in supramolecular association with other components. The aromaticity of the flat benzofuran residue plays an important role in directing either homo- or heteromolecular ,,, stacking in the first three structures, while the occurrence of a chiral architecture directed by multiple hydrogen bonding is the dominant feature in the fourth. [source]


    Probing the supramolecular interaction synthons of 1-benzofuran-2,3-dicarboxylic acid in its monoanionic form

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2009
    Rajesh Koner
    1-Benzofuran-2,3-dicarboxylic acid (C10H6O5) is a dicarboxylic acid ligand which can readily engage in organometallic complexes with various metal ions. This ligand is characterized by an intramolecular hydrogen bond between the two carboxyl residues, and, as a monoanionic species, readily forms supramolecular adducts with different organic and inorganic cations. These are a 1:1 adduct with the dimethylammonium cation, namely dimethylammonium 3-carboxy-1-benzofuran-2-carboxylate, C2H8N+C10H5O5,, (I), a 2:1 complex with Cu2+ ions in which four neutral imidazole molecules also coordinate the metal atom, namely bis(3-carboxy-1-benzofuran-2-carboxylato-,O3)tetrakis(1H -imidazole-,N3)copper(II), [Cu(C10H5O5)2(C3H4N2)4], (II), and a 4:1 adduct with [La(H2O)7]3+ ions, namely heptaaquabis(3-carboxy-1-benzofuran-2-carboxylato-,O3)lanthanum 3-carboxy-1-benzofuran-2-carboxylate 1-benzofuran-2,3-dicarboxylic acid solvate tetrahydrate, [La(C10H5O5)2(H2O)7](C10H5O5)C10H6O54H2O, (III). In the crystal structure, complex (II) resides on inversion centres, while complex (III) resides on axes of twofold rotation. The crystal packing in all three structures reveals ,,, stacking interactions between the planar aromatic benzofuran residues, as well as hydrogen bonding between the components. The significance of this study lies in the first crystallographic characterization of the title framework, which consistently exhibits the presence of an intramolecular hydrogen bond and a consequent monoanionic-only nature. It shows further that the anion can coordinate readily to metal cations as a ligand, as well as acting as a monovalent counter-ion. Finally, the aromaticity of the flat benzofuran residue provides an additional supramolecular synthon that directs and facilitates the crystal packing of compounds (I),(III). [source]


    Crystallization and preliminary crystallographic analysis of endonuclease VIII in its uncomplexed form

    ACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2004
    Gali Golan
    The Escherichia coli DNA repair enzyme endonuclease VIII (EndoVIII or Nei) excises oxidized pyrimidines from damaged DNA substrates. It overlaps in substrate specificity with endonuclease III and may serve as a back-up for this enzyme in E. coli. The three-dimensional structure of Nei covalently complexed with DNA has been recently determined, revealing the critical amino-acid residues required for DNA binding and catalytic activity. Based on this information, several site-specific mutants of the enzyme have been tested for activity against various substrates. Although the crystal structure of the DNA-bound enzyme has been fully determined, the important structure of the free enzyme has not previously been analyzed. In this report, the crystallization and preliminary crystallographic characterization of DNA-free Nei are described. Four different crystal habits are reported for wild-type Nei and two of its catalytic mutants. Despite being crystallized under different conditions, all habits belong to the same crystal form, with the same space group (I222) and a similar crystallographic unit cell (average parameters a = 57.7, b = 80.2, c = 169.7,). Two of these crystal habits, I and IV, appear to be suitable for full crystallographic analysis. Crystal habit I was obtained by vapour diffusion using PEG 8000, glycerol and calcium acetate. Crystal habit IV was obtained by a similar method using PEG 400 and magnesium chloride. Both crystals are mechanically strong and stable in the X-ray beam once frozen under cold nitrogen gas. A full diffraction data set has recently been collected from a wild-type Nei crystal of habit I (2.6, resolution, 85.2% completeness, Rmerge = 9.8%). Additional diffraction data were collected from an Nei-R252A crystal of habit IV (2.05, resolution, 99.9% completeness, Rmerge = 6.0%) and an Nei-E2A crystal of habit IV (2.25, resolution, 91.7% completeness, Rmerge = 6.2%). These diffraction data were collected at 95,100 K using a synchrotron X-ray source and a CCD area detector. All three data sets are currently being used to obtain crystallographic phasing via molecular-replacement techniques. [source]


    Crystallization and preliminary X-ray studies of meso -2,3-butanediol dehydrogenase from Klebsiella pneumoniae IAM1063

    ACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2001
    Masato Otagiri
    Meso -2,3-butanediol dehydrogenase (meso -BDH) has been crystallized and preliminary X-ray crystallographic characterization of meso -BDH crystals has been performed. Single crystals of meso -BDH were prepared in two forms by the hanging-drop vapour-diffusion method using polyethylene glycol as a precipitant. Form I crystals belong to space group C2, with unit-cell parameters a = 215.5, b = 79.4, c = 134.8,, , = 98.22, and form II crystals belong to space group P21, with unit-cell parameters a = 69.16, b = 109.78, c = 127.28,, , = 102.29. The crystals diffracted to 2.0 and 1.7, resolutions, respectively, using synchrotron radiation. [source]


    Crystallization and preliminary crystallographic characterization of the PAS domains of EAG and ELK potassium channels

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2010
    Ricardo Adaixo
    Per,Arnt,Sim (PAS) domains are ubiquitous in nature; they are ,130-amino-acid protein domains that adopt a fairly conserved three-dimensional structure despite their low degree of sequence homology. These domains constitute the N-terminus or, less frequently, the C-terminus of a number of proteins, where they exert regulatory functions. PAS-containing proteins generally display two or more copies of this motif. In this work, the crystallization and preliminary analysis of the PAS domains of two eukaryotic potassium channels from the ether--go-go (EAG) family are reported. [source]


    Crystallization and preliminary crystallographic characterization of the iron-regulated outer membrane lipoprotein FrpD from Neisseria meningitidis

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2010
    Ekaterina Sviridova
    Fe-regulated protein D (FrpD) is a Neisseria meningitidis outer membrane lipoprotein that may be involved in the anchoring of the secreted repeat in toxins (RTX) protein FrpC to the outer bacterial membrane. However, the function and biological roles of the FrpD and FrpC proteins remain unknown. Native and selenomethionine-substituted variants of recombinant FrpD43,271 protein were crystallized using the sitting-drop vapour-diffusion method. Diffraction data were collected to a resolution of 2.25, for native FrpD43,271 protein and to a resolution of 2.00, for selenomethionine-substituted FrpD43,271 (SeMet FrpD43,271) protein. The crystals of native FrpD43,271 protein belonged to the hexagonal space group P62 or P64, while the crystals of SeMet FrpD43,271 protein belonged to the primitive orthorhombic space group P212121. [source]


    Preliminary X-ray crystallographic analysis of the d -xylulose 5-phosphate phosphoketolase from Lactococcus lactis

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2010
    Georgiana Petrareanu
    Phosphoketolases are thiamine diphosphate-dependent enzymes which play a central role in the pentose-phosphate pathway of heterofermentative lactic acid bacteria. They belong to the family of aldehyde-lyases and in the presence of phosphate ion cleave the carbon,carbon bond of the specific substrate d -xylulose 5-phosphate (or d -fructose 6-phosphate) to give acetyl phosphate and d -glyceraldehyde 3-phosphate (or d -erythrose 4-phosphate). Structural information about phosphoketolases is particularly important in order to fully understand their mechanism as well as the steric course of phosphoketolase-catalyzed reactions. Here, the purification, preliminary crystallization and crystallographic characterization of d -xylulose 5-phosphate phosphoketolase from Lactococcus lactis are reported. The presence of thiamine diphosphate during purification was essential for the enzymatic activity of the purified protein. The crystals belonged to the monoclinic space group P21. Diffraction data were obtained to a resolution of 2.2,. [source]


    Preliminary crystallographic characterization of the Grb2 SH2 domain in complex with a FAK-derived phosphotyrosyl peptide

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2010
    Hsiao-Hsin Chen
    Growth factor receptor-bound protein 2 (Grb2) is an adaptor protein with a single SH2 domain that specifically binds to focal adhesion kinase (FAK) when residue Tyr925 of FAK is phosphorylated. The Grb2,FAK interaction is associated with cellular integrin-activated signal transduction events leading to the activation of the Ras-MAPK pathway. Crystals of the Grb2 SH2 domain in complex with a phosphopeptide corresponding to residues 921,930 of FAK have been obtained using the sitting-drop vapour-diffusion technique. The crystals belonged to space group P3121, with unit-cell parameters a = b = 102.7, c = 127.6,, , = , = 90.0, , = 120.0. A diffraction data set was collected from a flash-cooled crystal at 100,K to 2.49, resolution using synchrotron radiation. Structure determination by molecular replacement and analysis of the detailed structure of the complex are currently in progress. [source]


    Crystallization and preliminary crystallographic characterization of glutamine synthetase from Medicago truncatula

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 12 2009
    Ana Rita Seabra
    The condensation of ammonium and glutamate into glutamine catalyzed by glutamine synthetase (GS) is a fundamental step in nitrogen metabolism in all kingdoms of life. In plants, this is preceded by the reduction of inorganic nitrogen to an ammonium ion and therefore effectively articulates nitrogen fixation and metabolism. Although the three-dimensional structure of the dodecameric bacterial GS was determined quite some time ago, the quaternary architecture of the plant enzyme has long been assumed to be octameric, mostly on the basis of low-resolution electron-microscopy studies. Recently, the crystallographic structure of a monocotyledonous plant GS was reported that revealed a homodecameric organization. In order to unambiguously establish the quaternary architecture of GS from dicotyledonous plants, GS1a from the model legume Medicago truncatula was overexpressed, purified and crystallized. The collection of synchrotron diffraction data to 2.35, resolution allowed the determination of the three-dimensional structure of this enzyme by molecular replacement. [source]


    Crystallization and preliminary X-ray crystallographic characterization of a public CMV-specific TCR in complex with its cognate antigen

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 11 2009
    Jean-Baptiste Reiser
    The T-cell response to human cytomegalovirus is characterized by a dramatic reduction of clonal diversity in patients undergoing chronic inflammation or immunodepression. In order to check whether all the selected high-avidity T-cell clones recognize the immunodominant pp65 peptide antigen pp65495,503 (NLVPMVATV) presented by the major histocompatibility complex (MHC) molecule HLA-A2 in a similar manner, several public high-affinity T-cell receptors (TCRs) specific for the pp65495,503,HLA-A2 complex have been investigated. Expression, purification and crystallization were performed and preliminary crystallographic data were collected to 4.7, resolution for the RA15 TCR in complex with the pp65495,503,HLA-A2 complex. Comparison of the RA15,pp65495,503,HLA-A2 complex molecular-replacement solution with the structure of another high-affinity pp65495,503,HLA-A2-specific TCR, RA14, shows a shared docking mode, indicating that the clonal focusing could be accompanied by the selection of a most favoured peptide-readout mode. However, the position of the RA15 V, domain is significantly shifted, suggesting a different interatomic interaction network. [source]


    Crystallization and preliminary X-ray analysis of mannosyl-3-phosphoglycerate synthase from Thermus thermophilus HB27

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 10 2009
    Susana Gonalves
    Mannosylglycerate (MG) is a compatible solute that is widespread in marine organisms that are adapted to hot environments, with its intracellular pool generally increasing in response to osmotic stress. These observations suggest that MG plays a relevant role in osmoadaptation and thermoadaptation. The pathways for the synthesis of MG have been characterized in a number of thermophilic and hyperthermophilic organisms. Mannosyl-3-phosphoglycerate synthase (MpgS) is a key enzyme in the biosynthesis of MG. Here, the purification, crystallization and preliminary crystallographic characterization of apo MpgS from Thermus thermophilus HB27 are reported. The addition of Zn2+ to the crystallization buffer was essential in order to obtain crystals. The crystals belonged to one of the enantiomorphic tetragonal space groups P41212 or P43212, with unit-cell parameters a = b = 113, c = 197,. Diffraction data were obtained to a resolution of 2.97,. [source]


    Crystallization and preliminary crystallographic characterization of the extrinsic PsbP protein of photosystem II from Spinacia oleracea

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2009
    J. Kohoutov
    Preliminary X-ray diffraction analysis of the extrinsic PsbP protein of photosystem II from spinach (Spinacia oleracea) was performed using N-terminally His-tagged recombinant PsbP protein overexpressed in Escherichia coli. Recombinant PsbP protein (thrombin-digested recombinant His-tagged PsbP) stored in bis-Tris buffer pH 6.00 was crystallized using the sitting-drop vapour-diffusion technique with PEG 550 MME as a precipitant and zinc sulfate as an additive. SDS,PAGE analysis of a dissolved crystal showed that the crystals did not contain the degradation products of recombinant PsbP protein. PsbP crystals diffracted to 2.06, resolution in space group P212121, with unit-cell parameters a = 38.68, b = 46.73, c = 88.9,. [source]


    Crystallization and initial crystallographic characterization of a vicilin-type seed storage protein from Pinus koraiensis

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 12 2007
    Tengchuan Jin
    The cupin superfamily of proteins includes the 7S and 11S seed storage proteins. Many members of this family of proteins are known allergens. In this study, the Korean pine (Pinus koraiensis) vicilin-type 7S seed storage protein was isolated from defatted pine-nut extract and purified by sequential gel-filtration and anion-exchange chromatography. Well diffracting single crystals were obtained by the vapor-diffusion method in hanging drops. The crystals belong to the primitive cubic space group P213, with unit-cell parameters a = b = c = 148.174,. Two vicilin molecules were present in the asymmetric unit and the Matthews coefficient was determined to be 2.90,3,Da,1, with a corresponding solvent content of ,58%. A molecular-replacement structural solution has been obtained using the program Phaser. Refinement of the structure is currently under way. [source]


    Crystallization and preliminary crystallographic characterization of GumK, a membrane-associated glucuronosyltransferase from Xanthomonas campestris required for xanthan polysaccharide synthesis

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2006
    Mximo Barreras
    GumK is a membrane-associated inverting glucuronosyltransferase that is part of the biosynthetic route of xanthan, an industrially important exopolysaccharide produced by Xanthomonas campestris. The enzyme catalyzes the fourth glycosylation step in the pentasaccharide-P-P-polyisoprenyl assembly, an oligosaccharide diphosphate lipid intermediate in xanthan biosynthesis. GumK has marginal homology to other glycosyltransferases (GTs). It belongs to the CAZy family GT 70, for which no structure is currently available, and indirect biochemical evidence suggests that it also belongs to the GT-B structural superfamily. Crystals of recombinant GumK from X. campestris have been grown that diffract to 1.9, resolution. Knowledge of the crystal structure of GumK will help in understanding xanthan biosynthesis and its regulation and will also allow a subsequent rational approach to enzyme design and engineering. The multiwavelength anomalous diffraction approach will be used to solve the phase problem. [source]