Home About us Contact
|
Home About us Contact | ||
|
|
||
Group P212121 (group + p212121)
Kinds of Group P212121 Selected AbstractsSynthesis, growth and characterization of single crystals of pure and thiourea doped L-glutamic acid hydrochlorideCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2007R. Sathyalakshmi Abstract L(+)Glutamic acid hydrochloride [HOOC (CH2)2CH(NH2) COOH·HCl], a monoamino dicarboxylic acid salt of L-Glutamic acid was synthesized and the synthesis was confirmed by FTIR analysis. Solubility of the material in water was determined. Pure and Thiourea doped L-Glutamic acid hydrochloride crystals were grown by low temperature solution growth using solvent evaporation technique. XRD, UV-Vis-NIR analyses were carried out for both pure and thiourea doped crystals. The crystals were qualitatively analyzed by EDAX analysis and the presence of thiourea was confirmed. The cell parameters of L-Glutamic acid hydrochloride have been determined as a = 5.151 Å, b = 11.79 Å, c = 13.35 Å by X-ray diffraction analysis and it crystallizes in orthorhombic space group P212121. UV-Vis-NIR spectra analysis showed good optical transmission in the entire visible region for both pure and doped crystals. Micro hardness of both pure and doped crystals has been determined using Vickers micro hardness tester. The SHG efficiencies of both pure and doped crystals were determined using Kurtz powder test and pure L-Glutamic acid hydrochloride crystal was found to possess better efficiency than thiourea doped L-Glutamic acid hydrochloride crystals. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Configuration, conformation and crystal structure of rabdosianin bCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2005Bao Lin Li Abstract Rabdosianin B, 7,20-epoxy-7,-hydroxy-1,,6,,11,,15,-tetraacetoxy- ent -kaur-16-ene, C28H38O10, was the first isolated from Isodon henryi. It consists of three six-membered rings A, B, C and one five-membered ring D. The fused-ring system A, B and C are in chair, boat and chair conformations, respectively, and ring D is in an envelope conformation, on the basis of NMR and X-ray diffraction analysis. The crystal of rabdosianin B is in orthorhombic crystal system with space group P212121, lattice constants: a = 9.969(1) Å, b = 15.400(3) Å, and c = 17.624(3) Å, Z = 4. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Structure, growth and optical properties of Zn0.24Ni0.76(SO4)·7H2O single crystalCRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2004Xinxin Zhuang Abstract A new crystalline complex zinc nickel sulfate heptahydrate (ZNSH) has been prepared. The crystal structure was investigated by x-ray single crystal diffraction method and the empirical formula is Zn0.24Ni0.76(SO4)·7H2O. The ZNSH crystal belongs to the orthorhombic space group P212121 with cell parameters a = 6.7742(14) Å, b = 11.748(2) Å, c = 12.009(2) Å. The deep-green ZNSH single crystal with dimension of 30 × 25 × 25 mm3 has been grown by the cooling solution method. The constituent ratio of ZNSH crystal grown from various compounding solutions at temperature range 40-50 °C is approximate invariant. The crystal absorption spectra with theoretical analysis are reported. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis, Structure and Magnetic Properties of a Tetranuclear Copper(II) Complex on the Basis of a 2-Substituted Glucopyranoside Schiff Base Ligand,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2006Anja Burkhardt Abstract Condensation of a derivatized 2-aminoglucose fragment with salicylaldehyde affords the new sugar-based Schiff base ligand benzyl 4,6- O -benzylidene-2-deoxy-2-salicylideneamino-,- D -glucopyranoside (H2L). The reaction of the dibasic ligand H2L with [Cu(CH3COO)2]·H2O leads to the formation of the tetranuclear copper(II) complex [{Cu(L)}4] (3) by a self-assembly process. The X-ray structural analysis of complex 3 which crystallizes together with two molecules of chloroform and one molecule of ethanol in the space group P212121 revealed for all copper atoms a NO3 coordination environment with a square-planar geometry. The tetranuclear molecule 3 consists of four chiral building blocks {Cu(L)} with the rare 2,3-coordination of the trans -configured donor atoms of the sugar backbone. The observed coordination mode of the building blocks exemplifies how chitosan-derived polysaccharide ligands can act as a chiral support for transition-metal complexes. The C-3 alcoholate oxygen atoms of the carbohydrate unit is bridging adjacent {Cu(L)} moieties resulting in an eight-membered Cu4O4 ring with a boat-like conformation. Temperature-dependent magnetic measurements of 3 indicate moderate antiferromagnetic interactions between the four copper(II) ions with a coupling constant of J = ,130 cm,1.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] On the purity of 2-[ortho -anilinyl]-1,3-benzoxazole derived from 2H -3,1-benzoxazine-2,4(1H)dione (isatoic anhydride) [1,2],JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 2 2010Karen M. Button The Lewis acid catalyzed synthesis and chromatographic purification of isatoic anhydride-derived 2-(2,-anilinyl)-1,3-benzoxazole (2) can result in the co-isolation of 2 and a light pink colored impurity (<5%). This latter species has been identified (NMR, single crystal X-ray diffraction, mp) as 2,-hydroxy-2-aminobenzanilide (3), which represents a predictable intermediate in the formation of 2. Compound 3 crystallizes in an orthorhombic crystal system of space group P212121 with four molecules in the unit cell (, = , = , = 90°; a = 6.715 (2) Å, b = 12.100 (4) Å, c = 13.321 (4) Å; V = 1082.2 (6) Å3). Pure 2 is characterized as a colorless, high-melting solid; unlike the dark colored oil that is isolated if 2 contains traces of 3. J. Heterocyclic Chem., (2010). [source] Comparison of the three-dimensional structures of a human Bence-Jones dimer crystallized on Earth and aboard US Space Shuttle Mission STS-95,JOURNAL OF MOLECULAR RECOGNITION, Issue 2 2003Simon S. Terzyan Abstract Crystals of a human (Sea) Bence-Jones dimer were produced in a capillary by vapor diffusion under microgravity conditions in the 9 day US Space Shuttle Mission STS-95. In comparison to ground-based experiments, nucleation was facile and spontaneous in space. Appearance of a very large (8,×,1.6,×,1.0,mm) crystal in a short time period is a strong endorsement for the use of microgravity to produce crystals sufficiently large for neutron diffraction studies. The Sea dimer crystallized in the orthorhombic space group P212121, with a,=,48.9,Å, b,=,85.2,Å, and c,=,114.0,Å. The crystals grown in microgravity exhibited significantly lower mosaicities than those of ground-based crystals and the X-ray diffraction data had a lower overall B factor. Three-dimensional structures determined by X-ray analysis at two temperatures (100 and 293,K) were indistinguishable from those obtained from ground-based crystals. However, both the crystallographic R factor and the free R factor were slightly lower in the models derived from crystals produced in microgravity. The major difference between the two crystal growth systems is a lack of convection and sedimentation in a microgravity environment. This environment resulted in the growth of much larger, higher-quality crystals of the Sea Bence-Jones protein. Structurally, heretofore unrecognized grooves on the external surfaces of the Sea and other immunoglobulin-derived fragments are regular features and may offer supplementary binding regions for super antigens and other elongated ligands in the bloodstream and perivascular tissues. Copyright © 2003 John Wiley & Sons, Ltd. [source] Structural characterization of anhydrous naloxone- and naltrexone hydrochloride by high resolution laboratory X-ray powder diffraction and thermal analysisJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2007Kunihisa Sugimoto Abstract The crystal structures of the analgesic compounds anhydrous naloxone and naltrexone hydrochloride were determined ab initio from high resolution laboratory X-ray powder diffraction data. Both compounds crystallize in the orthorhombic space group P212121 with lattice parameters of a,=,14.6588(10) Å, b,=,17.4363(9) Å, c,=,7.96200(22) Å, and V,=,2035.06(23) Å3 for naloxone hydrochloride and a,=,15.4560(5) Å, b,=,14.9809(4) Å, c,=,7.84121(18) Å, and V,=,1815.58(11) Å3 for naltrexone hydrochloride. The crystal structure of anhydrous naloxone hydrochloride forms one-dimensional chains through hydrogen bonds. In the crystal structure of anhydrous naltrexone hydrochloride, two-dimensional sheets are formed by hydrogen bonds. The dehydration processes of naloxone hydrochloride dehydrate and naltrexone hydrochloride tetrahydrate was analyzed by DTA, DSC, TG, and MG. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 3316,3323, 2007 [source] Chiral Crystal Structure of Racemic Binaphthyl Poly(ether ketone) MacrocyclesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 7 2005Xing Wang Abstract Summary: The crystal structure of rigid, hollow, racemic binaphthyl poly(ether ketone) macrocycles has been elucidated by single crystal X-ray analysis. Multitudinal interactions were identified within the chiral space group P212121. The structural analysis revealed that this macrocyclic compound contains an elliptic chiral cavity with a size of 9.80,×,5.18 Å, which is similar to that of cyclodextrins. The knowledge about the interaction sites and the structure of the binaphthyl-based macrocycle provides a unique opportunity to understand its molecular or chiral recognition properties. Space-filling representation of the single (R)-macrocycle. [source] Crystal structure of a dimeric form of streptococcal pyrogenic exotoxin A (SpeA1)PROTEIN SCIENCE, Issue 9 2004Matthew D. Baker Abstract Streptococcal pyrogenic exotoxin A (SpeA1) is a bacterial superantigen associated with scarlet fever and streptococcal toxic shock syndrome (STSS). SpeA1 is found in both monomeric and dimeric forms, and previous work suggested that the dimer results from an intermolecular disulfide bond between the cysteines at positions 90 of each monomer. Here, we present the crystal structure of the dimeric form of SpeA1. The toxin crystallizes in the orthorhombic space group P212121, with two dimers in the crystallographic asymmetric unit. The final structure has a crystallographic R-factor of 21.52% for 7248 protein atoms, 136 water molecules, and 4 zinc atoms (one zinc atom per molecule). The implications of SpeA1 dimer on MHC class II and T-cell receptor recognition are discussed. [source] Ezetimibe anhydrate, determined from laboratory powder diffraction dataACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2010Jürgen Brüning Ezetimibe {systematic name: (3R,4S)-1-(4-fluorophenyl)-3-[(3S)-3-(4-fluorophenyl)-3-hydroxypropyl]-4-(4-hydroxyphenyl)azetidin-2-one}, C24H21F2NO3, is used to lower cholesterol levels by inhibiting cholesterol resorption in the human intestine. The crystal structure of ezetimibe anhydrate was solved from laboratory powder diffraction data by means of real-space methods using the program DASH [David et al. (2006). J. Appl. Cryst.39, 910,915]. Subsequent Rietveld refinement with TOPAS Academic [Coelho (2007). TOPAS Academic User Manual. Version 4.1. Coelho Software, Brisbane, Australia] led to a final Rwp value of 8.19% at 1.75,Å resolution. The compound crystallizes in the space group P212121 with one molecule in the asymmetric unit. The molecules are closely packed and two intermolecular hydrogen bonds form an extended hydrogen-bond architecture. [source] (E)- N2 -{4-[(E)-2-(4-Chlorobenzoyl)ethenyl]-3-methyl-1-phenyl-1H -pyrazol-5-yl}- N1,N1 -dimethylformamidine: polarized molecules within sheets of ,-stacked hydrogen-bonded chainsACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2010Jairo Quiroga The molecules of the title compound, C22H21ClN4O, are conformationally chiral, and in the space group P212121 each crystal contains only one conformational enantiomer. The intramolecular dimensions provide evidence for polarization of the electronic structure. Molecules are linked by a single C,H...,(arene) hydrogen bond into chains, which are themselves weakly linked into sheets by an aromatic ,,, stacking interaction. [source] 2-Methoxy-3-methyl-6-oxo-4-(2,3,4-tri- O -acetyl-,- d -xylopyranosylamino)-1,6-dihydropyrimidine-5-carbaldehyde 0.065-hydrate and 2-methylsulfanyl-6-oxo-4-(2,3,4-tri- O -acetyl-,- d -xylopyranosylamino)-1,6-dihydropyrimidine-5-carbaldehyde: hydrogen-bonded structures in one or three dimensionsACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2009Justo Cobo The organic components of 2-methoxy-3-methyl-6-oxo-4-(2,3,4-tri- O -acetyl-,- d -xylopyranosylamino)-1,6-dihydropyrimidine-5-carbaldehyde 0.065-hydrate, C18H23N3O10·0.065H2O, (I), which crystallizes with Z, = 2 in the space group P212121, are linked into a three-dimensional framework structure by a combination of four C,H...O hydrogen bonds. In 2-methylsulfanyl-6-oxo-4-(2,3,4-tri- O -acetyl-,- d -xylopyranosylamino)-1,6-dihydropyrimidine-5-carbaldehyde, C17H21N3O9S, (II), where the pyrimidine fragment is disordered with two different conformations for the methylsulfanyl substituent, molecules are linked into chains of rings by a combination of N,H...O and C,H...O hydrogen bonds. [source] A new polymorph of triphenylmethylamine: the effect of hydrogen bondingACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009Victor N. Khrustalev Crystallization of the hexane reaction mixture after treatment of LiGe(OCH2CH2NMe2)3 with Ph3CN3 gives rise to a new triclinic (space group P) polymorph of triphenylmethylamine, C19H17N, (I), containing dimers formed by N,H...N hydrogen bonds, whereas the structure of the known orthorhombic (space group P212121) polymorph of this compound, (II), consists of isolated molecules. While the dimers in (I) lie across crystallographic inversion centres, the molecules are not truly related by them. The centrosymmetric structure is due to the statistical disordering of the amino H atoms participating in the N,H...N hydrogen-bonding interactions, and thus the inversion centre is superpositional. The conformations and geometric parameters of the molecules in (I) and (II) are very similar. It was found that the polarity of the solvent does not affect the capability of triphenylmethylamine to crystallize in the different polymorphic modifications. The orthorhombic polymorph, (II), is more thermodynamically stable under normal conditions than the triclinic polymorph, (I). The experimental data indicate the absence of a phase transition in the temperature interval 120,293,K. The densities of (I) (1.235,Mg,m,3) and (II) (1.231,Mg,m,3) at 120,K are practically equal. It would seem that either the kinetic factors or the effects of the other products of the reaction facilitating the hydrogen-bonded dimerization of triphenylmethylamine molecules are the determining factor for the isolation of the triclinic polymorph (I) of triphenylmethylamine. [source] Salts of maleic and fumaric acids with oxine: the role of isomeric acids in hydrogen-bonding patternsACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009S. Franklin Both maleic and fumaric acid readily form adducts or complexes with other organic molecules. The 1:1 adduct formed by quinolin-8-ol (oxine) with maleic and fumaric acid are salts, namely 8-hydroxyquinolinium hydrogen maleate, C9H8NO+·C4H3O4,, (I), and 8-hydroxyquinolinium hydrogen fumarate, C9H8NO+·C4H3O4,, (II). The cations and anions of both salts are linked by ionic N+,H...O, hydrogen bonds. The maleate salt crystallizes in the space group P212121, while the fumarate salt crystallizes in P. The maleic and fumaric acids in their complex forms exist as semimaleate and semifumarate ions (mono-ionized state), respectively. Classical N,H...O and O,H...O hydrogen bonds, together with short C,H...O contacts, generate an extensive hydrogen-bonding network. The crystal structures of the maleate and fumarate salts of oxine have been elucidated to study the importance of noncovalent interactions in the aggregation and interaction patterns of biological molecules. The structures of the salts of the Z and E isomers of butenedioic acid (maleic and fumaric acid, respectively) with quinolin-8-ol are compared. [source] Two new non-centrosymmetric lithium salts of glycine: bis(glycine) lithium chromate monohydrate and bis(glycine) lithium molybdateACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2006Michel Fleck In bis(glycine) lithium chromate monohydrate {systematic name: poly[aquadi-,-glycinato-,-tetraoxochromato(VI)-dilithium(I)]}, [CrLi2(C2H5NO2)2O4(H2O)]n, (I) (space group P212121), and bis(glycine) lithium molybdate {systematic name: poly[di-,-glycinato-,-tetraoxomolybdato(VI)-dilithium(I)]}, [Li2Mo(C2H5NO2)2O4]n, (II) (space group P21), all atoms are located on general positions. The crystal structure of (I) is characterized by infinite chains of corner-sharing [LiO4] tetrahedra, which are connected by glycine molecules to form layers. [CrO4] tetrahedra are attached to the [LiO4] tetrahedra. Compound (II) contains dimers of [LiO4] tetrahedra which are connected by [MoO4] tetrahedra to form chains, which are in turn connected by glycine molecules to form double layers. [source] trans -(dl -Isoleucinato- N,O)[tris(2-aminoethyl)amine-,4N]cobalt(III) diperchlorateACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2001Jiwen Cai The racemic title compound, trans -[N,N -bis(2-aminoethyl)-1,2-ethanediamine-,4N](dl -isoleucinato- N,O)cobalt(III) diperchlorate, [Co(C6H18N4)(C6H12NO2)](ClO4)2, crystallizes in the enantiomorphous space group P212121 with Z = 12 (Z, = 3). Each of the three cations in the asymmetric unit represents a different chirality of the isoleucine ligand; two of them are R (or d) and the third is the S (or l) enantiomer. The mixture crystallizes in a so-called unbalanced crystallization, in which the cations adopt a chiral array of composition RRS or SSR, depending on the crystal selected for data collection. [source] (S)-Tricarbonyl[(1,2,3,4-,)-(5R,6S)-1-chloro-5,6-dimethoxycyclohexa-1,3-diene]iron(0)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2000Silvia Russi The title compound, [Fe(C8H11ClO2)(CO)3], has been synthesized, isolated and characterized by single-crystal X-ray diffraction. The molecule crystallizes in the orthorhombic space group P212121. The metal,ligand arrangement is typical of (1,3-diene)tricarbonyliron complexes. [source] Atomic resolution studies of haloalkane dehalogenases DhaA04, DhaA14 and DhaA15 with engineered access tunnelsACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2010A. Stsiapanava The haloalkane dehalogenase DhaA from Rhodococcus rhodochrous NCIMB 13064 is a bacterial enzyme that shows catalytic activity for the hydrolytic degradation of the highly toxic industrial pollutant 1,2,3-trichloropropane (TCP). Mutagenesis focused on the access tunnels of DhaA produced protein variants with significantly improved activity towards TCP. Three mutants of DhaA named DhaA04 (C176Y), DhaA14 (I135F) and DhaA15 (C176Y + I135F) were constructed in order to study the functional relevance of the tunnels connecting the buried active site of the protein with the surrounding solvent. All three protein variants were crystallized using the sitting-drop vapour-diffusion technique. The crystals of DhaA04 belonged to the orthorhombic space group P212121, while the crystals of DhaA14 and DhaA15 had triclinic symmetry in space group P1. The crystal structures of DhaA04, DhaA14 and DhaA15 with ligands present in the active site were solved and refined using diffraction data to 1.23, 0.95 and 1.22,Å, resolution, respectively. Structural comparisons of the wild type and the three mutants suggest that the tunnels play a key role in the processes of ligand exchange between the buried active site and the surrounding solvent. [source] Pseudo-merohedral twinning and noncrystallographic symmetry in orthorhombic crystals of SIVmac239 Nef core domain bound to different-length TCR, fragmentsACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2010Walter M. Kim HIV/SIV Nef mediates many cellular processes through interactions with various cytoplasmic and membrane-associated host proteins, including the signalling , subunit of the T-cell receptor (TCR,). Here, the crystallization strategy, methods and refinement procedures used to solve the structures of the core domain of the SIVmac239 isolate of Nef (Nefcore) in complex with two different TCR, fragments are described. The structure of SIVmac239 Nefcore bound to the longer TCR, polypeptide (Leu51,Asp93) was determined to 3.7,Å resolution (Rwork = 28.7%) in the tetragonal space group P43212. The structure of SIVmac239 Nefcore in complex with the shorter TCR, polypeptide (Ala63,Arg80) was determined to 2.05,Å resolution (Rwork = 17.0%), but only after the detection of nearly perfect pseudo-merohedral crystal twinning and proper assignment of the orthorhombic space group P212121. The reduction in crystal space-group symmetry induced by the truncated TCR, polypeptide appears to be caused by the rearrangement of crystal-contact hydrogen-bonding networks and the substitution of crystallographic symmetry operations by similar noncrystallographic symmetry (NCS) operations. The combination of NCS rotations that were nearly parallel to the twin operation (k, h, ,l) and a and b unit-cell parameters that were nearly identical predisposed the P212121 crystal form to pseudo-merohedral twinning. [source] Imperfect pseudo-merohedral twinning in crystals of fungal fatty acid synthaseACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2009Simon Jenni The recent high-resolution structures of fungal fatty acid synthase (FAS) have provided new insights into the principles of fatty acid biosynthesis by large multifunctional enzymes. The crystallographic phase problem for the 2.6,MDa fungal FAS was initially solved to 5,Å resolution using two crystal forms from Thermomyces lanuginosus. Monoclinic crystals in space group P21 were obtained from orthorhombic crystals in space group P212121 by dehydration. Here, it is shown how this space-group transition induced imperfect pseudo-merohedral twinning in the monoclinic crystal, giving rise to a Moiré pattern-like interference of the two twin-related reciprocal lattices. The strategy for processing the twinned diffraction images and obtaining a quantitative analysis is presented. The twinning is also related to the packing of the molecules in the two crystal forms, which was derived from self-rotation function analysis and molecular-replacement solutions using a low-resolution electron microscopy map as a search model. [source] Structure of a bovine secretory signalling glycoprotein (SPC-40) at 2.1,Å resolutionACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2006Janesh Kumar A recently discovered new class of 40,kDa glycoproteins forms a major component of the secretory proteins in the dry secretions of non-lactating animals. These proteins are implicated as protective signalling factors that determine which cells are to survive during the processes of drastic tissue remodelling. In order to understand its role in the remodelling of mammary glands, the detailed three-dimensional structure of the bovine signalling glycoprotein (SPC-40) has been determined using X-ray crystallography. SPC-40 was purified from bovine dry secretions and crystallized using the hanging-drop vapour-diffusion method. The crystals belong to the orthorhombic space group P212121, with unit-cell parameters a = 62.6, b = 67.4, c = 106.9,Å. The protein was also cloned in order to determine its complete amino-acid sequence. Its three-dimensional structure has been determined using data to 2.1,Å resolution. The amino-acid sequence determination of SPC-40 reveals two potential N-glycosylation sites at Asn39 and Asn345, but electron density for a glycan chain was only present at Asn39. The protein adopts a conformation with the classical (,/,)8 -barrel fold of triosephosphate isomerase (TIM barrel; residues 1,237 and 310,360) with the insertion of a small ,+, domain (residues 240,307) similar to that observed in chitinases. However, the substitution of Leu for Glu in the consensus catalytic sequence in SPC-40 caused a loss of chitinase activity. Furthermore, the chitin-binding groove in SPC-40 is considerably distorted owing to unfavourable conformations of several residues, including Trp78, Tyr120, Asp186 and Arg242. Three surface loops, His188,His197, Phe202,Arg212 and Tyr244,Pro260, have exceptionally high B factors, suggesting large-scale flexibility. Fluorescence studies indicate that various sugars bind to SPC-40 with low affinities. [source] Structure of d(TGCGCG)·d(CGCGCA) in two crystal forms: effect of sequence and crystal packing in Z-DNAACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2005S. Thiyagarajan The sequence d(TGCGCG)·d(CGCGCA) crystallized in two crystal forms, orthorhombic and hexagonal, in the presence of cobalt hexammine chloride, a known inducer of the left-handed Z-form of DNA. The crystal structures have been solved and refined at 1.71,Å resolution in space group P212121 and 2.0,Å resolution in space group P65. The orthorhombic structure contains one Z-DNA hexamer duplex, while the hexagonal structure contains two hexamer duplexes in the structure. Of the latter, one is situated on a crystallographic sixfold screw axis, leading to disorder. This paper reports the effects of sequence and crystal packing on the structure of Z-type DNA. The structures lend additional support to the authors' earlier conclusion that a stretch of four C·G base pairs is sufficient to nucleate and define the regular model of the left-handed helix based on the structure of d(CGCGCG)2. [source] Structural consequences of hen egg-white lysozyme orthorhombic crystal growth in a high magnetic field: validation of X-ray diffraction intensity, conformational energy searching and quantitative analysis of B factors and mosaicityACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2005Shinya Saijo A novel method has been developed to improve protein-crystal perfection during crystallization in a high magnetic field and structural studies have been undertaken. The three-dimensional structure of orthorhombic hen egg-white (HEW) lysozyme crystals grown in a homogeneous and static magnetic field of 10,T has been determined and refined to a resolution of 1.13,Å and an R factor of 17.0%. The 10,T crystals belonged to space group P212121, with unit-cell parameters a = 56.54,(3), b = 73.86,(6), c = 30.50,(2),Å and one molecule per asymmetric unit. A comparison of the structures of the 0,T and 10,T crystals has been carried out. The magnitude of the structural changes, with a root-mean-square deviation value of 0.75,Å for the positions of all protein atoms, is similar to that observed when an identical protein structure is resolved in two different crystalline lattices. The structures remain similar, with the exception of a few residues e.g. Arg68, Arg73, Arg128 and Gln121. The shifts of the arginine residues result in very significant structural fluctuations, which can have large effects on a protein's crystallization properties. The high magnetic field contributed to an improvement in diffraction intensity by (i) the displacement of the charged side chains of Arg68 and Arg73 in the flexible loop and of Arg128 at the C-terminus and (ii) the removal of the alternate conformations of the charged side chains of Arg21, Lys97 or Arg114. The improvement in crystal perfection might arise from the magnetic effect on molecular orientation without structural change and differences in molecular interactions. X-ray diffraction and molecular-modelling studies of lysozyme crystals grown in a 10,T field have indicated that the field contributes to the stability of the dihedral angle. The average difference in conformational energy has a value of ,578,kJ,mol,1 per charged residue in favour of the crystal grown in the magnetic field. For most protein atoms, the average B factor in the 10,T crystal shows an improvement of 1.8,Å2 over that for the 0,T control; subsequently, the difference in diffraction intensity between the 10,T and 0,T crystals corresponds to an increase of 22.6% at the resolution limit. The mosaicity of the 10,T crystal was better than that of the 0,T crystal. More highly isotropic values of 0.0065, 0.0049 and 0.0048° were recorded along the a, b and c axes, respectively. Anisotropic mosaicity analysis indicated that crystal growth is most perfect in the direction that corresponds to the favoured growth direction of the crystal, and that the crystal grown in the magnetic field had domains that were three times the volume of those of the control crystal. Overall, the magnetic field has improved the quality of these crystals and the diffracted intensity has increased significantly with the magnetic field, leading to a higher resolution. [source] Crystallization and preliminary X-ray crystallographic analysis of a non-specific lipid-transfer protein with antipathogenic activity from Phaseolus mungoACTA CRYSTALLOGRAPHICA SECTION D, Issue 12-2 2004Shao-Yun Wang A 9,kDa non-specific lipid-transfer protein (nsLTP) from mung bean (Phaseolus mungo) seeds, displaying antifungal activity, antibacterial activity and lipid-transfer activity, was crystallized at 297,K using ammonium sulfate as a precipitant by means of the hanging-drop vapour-diffusion method. Native X-ray diffraction data were collected to a resolution of 2.4,Å. The crystals are rhombohedral, belonging to space group P212121, with unit-cell parameters a = 38.671, b = 51.785, c = 55.925,Å. Assuming the presence of one molecule in the crystallographic asymmetric unit results in a Matthews coefficient (VM) of approximately 3.0,Å3,Da,1, corresponding to a solvent content of about 58%. [source] Expression, crystallization and preliminary structural analysis of the ectoplasmic region of apical membrane antigen 1 from Plasmodium vivax, a malaria-vaccine candidateACTA CRYSTALLOGRAPHICA SECTION D, Issue 11 2004Brigitte Vulliez-Le Normand Apical membrane antigen 1 (AMA1), a type 1 transmembrane protein present in the microneme organelles of Plasmodium, is a leading malaria-vaccine candidate. The ectoplasmic region of AMA1 from P. vivax has been expressed in Pichia pastoris and crystallized in two different forms: an orthorhombic form (space group P212121, unit-cell parameters a = 54.1, b = 76.1, c = 103.9,Å) and a monoclinic form (space group C2, unit-cell parameters a = 150.0, b = 53.8, c = 60.3,Å, , = 113.2°). Native data have been collected to 2.0,Å resolution for the orthorhombic form and 1.8,Å for the monoclinic form. A platinum derivative was prepared for the orthorhombic and monoclinic crystals using K2PtCl4 and data were collected at several wavelengths to obtain phases by the MAD technique. A partial model has been built from the electron-density maps of both forms and refinement is in progress. [source] Crystallization and preliminary analysis of a water-forming NADH oxidase from Lactobacillus sanfranciscensisACTA CRYSTALLOGRAPHICA SECTION D, Issue 11 2004George T. Lountos Single crystals have been obtained of NADH oxidase (Nox), a flavoenzyme cloned from Lactobacillus sanfranciscensis. The enzyme catalyzes the oxidation of two equivalents of NAD(P)H and reduces one equivalent of oxygen to yield two equivalents of water, without releasing hydrogen peroxide after the reduction of the first equivalent of NAD(P)H. The enzyme crystallizes in space group P212121, with unit-cell parameters a = 59.6, b = 92.6, c = 163.5,Å. The crystals diffract to 1.85,Å resolution using synchrotron radiation. Matthews coefficient calculations suggest the presence of two molecules per asymmetric unit (VM = 2.3,Å3,Da,1, 45.5% solvent content), which has been confirmed by the molecular-replacement solution using a search molecule derived from NADH peroxidase (PDB code 1f8w). [source] Crystallization and preliminary X-ray analysis of Escherichia coli MutT in binary and ternary complex formsACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2004Teruya Nakamura During replication, Escherichia coli MutT prevents the misincorporation of mutagenic 8-oxoguanine into nascent DNA strands opposite adenine by hydrolyzing 8-oxo-dGTP in nucleotide pools to 8-oxo-dGMP. E. coli MutT is the most widely investigated member of the Nudix hydrolase family, which is large and found in all organisms. By co-crystallization of MutT with 8-oxo-dGMP, a reaction product, crystals of the binary complex were obtained using ammonium sulfate as a precipitant. The crystals belong to space group P212121, with unit-cell parameters a = 37.9, b = 56.0, c = 59.4,Å. Assuming the presence of one protein,nucleotide complex in the asymmetric unit, the Matthews coefficient VM is 2.1,Å3,Da,1. Crystals of the ternary complex were prepared by soaking crystals of the binary complex in 1,mM MnCl2 solution. They diffracted to 1.96 and 2.56,Å resolution, respectively. [source] Crystallization and preliminary X-ray analysis of heparinase II from Pedobacter heparinusACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2004David Shaya Heparinase II from Pedobacter heparinus (formerly Flavobacterium heparinum), which acts on both heparin and heparan sulfate, is one of several glycosaminoglycan-degrading enzymes produced by this organism. This enzyme, with a molecular weight of 84,kDa, utilizes a lytic mechanism to cleave the ,(1,4) glycosidic bond between hexosamine (d -glucosamine) and l -iduronic or d -glucuronic acid, resulting in a product with an unsaturated sugar ring at the non-reducing end. The enzyme was crystallized by the hanging-drop vapour-diffusion method. The crystals belong to orthorhombic space group P212121 and diffract to 2,Å resolution. There are two molecules in the asymmetric unit, consistent with the finding that recombinant heparinase II functions as a dimer in solution. [source] Expression, purification, crystallization and preliminary X-ray diffraction data of methylmalonate-semialdehyde dehydrogenase from Bacillus subtilisACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2004Hélène Dubourg Methylmalonate-semialdehyde dehydrogenase from Bacillus subtilis was cloned and overexpressed in Escherichia coli. Suitable crystals for X-ray diffraction experiments were obtained by the hanging-drop vapour-diffusion method using ammonium sulfate as precipitant. The crystals belong to space group P212121, with unit-cell parameters a = 195.2, b = 192.5, c = 83.5,Å, and contain one tetramer per asymmetric unit. X-ray diffraction data were collected to 2.5,Å resolution using a synchrotron-radiation source. The crystal structure was solved by the molecular-replacement method. [source] Preparation and preliminary X-ray analysis of the catalytic module of ,-1,3-xylanase from the marine bacterium Vibrio sp.ACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2004,-1,3-xylanase (1,3-,- d -xylan xylanohydrolase; EC 3.2.1.32) is an enzyme capable of hydrolyzing ,-1,3-xylan. The newly cloned ,-1,3-xylanase from the marine bacterium Vibrio sp. AX-4 (XYL4) exhibited a modular structure consisting of three modules: an N-terminal catalytic module belonging to glycoside hydrolase family 26 and two C-terminal xylan-binding modules belonging to carbohydrate-binding module family 31. Despite substantial crystallization screening, crystallization of the recombinant XYL4 was not accomplished. However, the deletion mutant of XYL4, composed of a catalytic module without a xylan-binding module, was crystallized. The crystal belonged to space group P212121, with unit-cell parameters a = 51.6, b = 75.8, c = 82.0,Å. X-ray diffraction data were collected to 1.44,Å resolution. [source] | |||||||||||||