Home About us Contact
|
Home About us Contact | ||
|
|
||
Space Group C2 (space + group_c2)
Kinds of Space Group C2 Selected AbstractsTrigonal structures of ABe2BO3F2 (A = Rb, Cs, Tl) crystalsACTA CRYSTALLOGRAPHICA SECTION B, Issue 4 2009Colin D. McMillen Several interesting fluoroberyllium borates were synthesized hydrothermally and characterized by single-crystal X-ray diffraction. The crystal structures of RbBe2BO3F2 (RBBF; rubidium fluoroberyllium borate) and CsBe2BO3F2 (CBBF; caesium fluoroberyllium borate), previously determined in the space group C2, were reinvestigated for higher symmetry and found to have more suitable solutions in the space group R32. TlBe2BO3F2 (TBBF; thallium fluoroberyllium borate) was synthesized as a novel compound also having this trigonal structure type. Details of the space-group determination and unique structural features are discussed. These crystal structures were compared with that of KBe2BO3F2, revealing interesting structural trends within this family of compounds that are also discussed. A crystallographic explanation of the physical morphology is postulated. [source] High-pressure crystal structure of the non-linear optical compound BiB3O6 from two-dimensional powder diffraction dataACTA CRYSTALLOGRAPHICA SECTION B, Issue 1 2009R. E. Dinnebier Our recently proposed method for automatic detection, calibration and evaluation of Debye,Scherrer ellipses using pattern-recognition techniques and advanced signal filtering was applied to the two-dimensional powder diffraction data of the non-ferroelectric, non-centrosymmetric non-linear optical (NLO) compound ,-BiB3O6 as a function of pressure. At ambient conditions, ,-BiB3O6 crystallizes in the space group C2 (phase I). In the pressure range between P = 6.09 and 6.86,GPa, it exhibits a first-order phase transition into a structure with the space group C1 (P1) [phase II at P = 8.34,GPa: a = 7.4781,(6), b = 3.9340,(4), c = 6.2321,(6),Å, , = 93.73,(1), , = 102.93,(1), , = 90.76,(1)°, and V = 178.24,(3),Å3]. Non-linear compression behaviour over the entire pressure range is observed, which can be described by two Vinet relations in the ranges from P = 0.0 to 6.09,GPa, and from P = 6.86 to 11.6,GPa. The extrapolated bulk moduli of the high-pressure phases were determined to be K0 = 38,(1),GPa for phase I, and K0 = 114,(10),GPa for phase II. The crystal structures of both phases were refined against X-ray powder diffraction data measured at several pressures between 0.0 and 11.6,GPa. The structural phase transition of ,-BiB3O6 is mainly characterized by a reorientation of the [BO3]3, triangles, the [BO4]5, tetrahedra and the lone electron pair which is localized at Bi3+, in order to optimize crystal packing. [source] 7-Amino-2,5-dimethylpyrazolo[1,5- a]pyrimidine hemihydrate redetermined at 120,K: a three-dimensional hydrogen-bonded frameworkACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2006Jaime Portilla In the title compound, C8H10N4·0.5H2O, where the water molecules lie on twofold rotation axes in the space group C2, the components are linked by three hydrogen bonds, one each of O,H,N, N,H,N and N,H,O types, into a complex three-dimensional framework structure. [source] A new crystal form of human tear lipocalin reveals high flexibility in the loop region and induced fit in the ligand cavityACTA CRYSTALLOGRAPHICA SECTION D, Issue 10 2009Daniel A. Breustedt Tear lipocalin (TLC) with the bound artificial ligand 1,4-butanediol has been crystallized in space group P21 with four protein molecules in the asymmetric unit and its X-ray structure has been solved at 2.6,Å resolution. TLC is a member of the lipocalin family that binds ligands with diverse chemical structures, such as fatty acids, phospholipids and cholesterol as well as microbial siderophores and the antibiotic rifampin. Previous X-ray structural analysis of apo TLC crystallized in space group C2 revealed a rather large bifurcated ligand pocket and a partially disordered loop region at the entrace to the cavity. Analysis of the P21 crystal form uncovered major conformational changes (i) in ,-strands B, C and D, (ii) in loops 1, 2 and 4 at the open end of the ,-barrel and (iii) in the extended C-terminal segment, which is attached to the ,-barrel via a disulfide bridge. The structural comparison indicates high conformational plasticity of the loop region as well as of deeper parts of the ligand pocket, thus allowing adaptation to ligands that differ vastly in size and shape. This illustrates a mechanism for promiscuity in ligand recognition which may also be relevant for some other physiologically important members of the lipocalin protein family. [source] High-resolution structure of human cytoglobin: identification of extra N- and C-termini and a new dimerization modeACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2006Masatomo Makino Cytoglobin (Cgb) is a recently discovered member of the vertebrate haem-containing globin family. The structure of a new crystal form of wild-type human Cgb (space group C2) was determined at a resolution of 1.68,Å. The results show the presence of an additional helix in the N-terminal residues (4,20) prior to the A helix and an ordered loop structure in the C-terminal region (168,188), while these extended peptides were invisible owing to disorder in the previously reported structures using a P3221 crystal at a resolution of 2.4,Å. A detailed comparison of the two crystal structures shows differences in the conformation of the residues (i.e. Arg84) in the haem environment owing to a different dimeric arrangement. [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] A new crystal form of XT6 enables a significant improvement of its diffraction quality and resolutionACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2004Maya Bar Xylanases (1,4-,- d -xylan xylanhydrolases; EC 3.2.1.8) hydrolyze the 1,4-,- d -xylopyranosyl linkage of xylans. The detailed structural characterization of these enzymes is of interest for the elucidation of their catalytic mechanism and for their rational modification toward improved stability and specificity. An extracellular xylanase from Geobacillus stearothermophilus T-6 (XT6) has recently been cloned, overexpressed, purified and biochemically characterized. Previous crystallographic efforts resulted in a hexagonal crystal form, which subsequently proved to be of limited use for structural analysis, mainly because of its relatively poor diffraction quality and resolution. A systematic search for more suitable crystals of XT6 recently resulted in a new crystal form of this enzyme with significantly improved diffraction characteristics. The new crystals belong to a C -centred monoclinic crystal system (space group C2), with unit-cell parameters a = 121.5, b = 61.7, c = 89.1,Å, , = 119.7°. These crystals diffract X-rays to better than 1.5,Å resolution, showing a very clear diffraction pattern of relatively high quality. The crystals are mechanically strong and exhibit excellent radiation-stability when frozen under cold nitrogen gas. A full diffraction data set to 1.45,Å resolution (94.1% completeness, Rmerge = 7.0%) has been collected from flash-frozen crystals of the native enzyme at 95,K using synchrotron radiation. Crystals of the E159A/E265A catalytic double mutant of XT6 were found to be isomorphous to those of native XT6. They were used for a full measurement of 1.8,Å resolution diffraction data at 100,K (90.9% completeness; Rmerge = 5.0%). These data are currently being used for the high-resolution structure determination of XT6 and its mutant for mechanistic interpretations and rational introduction of thermostability. [source] Structure of the dodecamer r(GAUCACUUCGGU) with four 5,-overhang nucleotidesACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2004r(GAUCACUUCGGU) The crystal structure of an RNA dodecamer, r(GAUCACUUCGGU), was solved at 2.6,Å resolution by the molecular-replacement method and refined to an Rwork of 18.8% (Rfree = 22.8%) using 2494 reflections. The dodecamer crystallized in the monoclinic space group C2, with unit-cell parameters a = 71.34, b = 39.98, c = 32.47,Å, , = 104.7° and two independent strands in the asymmetric unit. The dodecamer adopts an octamer duplex structure with four 5,-overhang residues (G1A2U3C4), which form Watson,Crick base pairs with another four 5,-overhang residues of a symmetry-related duplex. The octamer duplex (ACUUCGGU) contains at its center four mismatched base pairs flanked by two Watson,Crick base pairs. The mismatched bases form two G·U wobble base pairs at the ends and two U·C base pairs at the center, with one base,base hydrogen bond N4(C)O4(U) and a water bridge connecting the N(3) of the cytosine and uridine. The present study reinforces the concept of the stability of the conformation of UUCG in RNA double-helical structures. [source] Crystallization and preliminary X-ray data investigation of the bacterial enterocin A immunity protein at 1.65,Å resolutionACTA CRYSTALLOGRAPHICA SECTION D, Issue 7 2003Bjørn Dalhus Crystals of the bacterial enterocin A immunity protein have been prepared by the hanging-drop vapour-diffusion technique at 293,K. The crystals diffract to better than 1.7,Å resolution and X-ray diffraction data to 1.65,Å have been collected at 110,K using synchrotron radiation. The enterocin A immunity protein crystals belong to the monoclinic crystal system, with unit-cell parameters a = 116.32, b = 42.35, c = 66.17,Å, , = 111.3°. The symmetry and systematic absences in the diffraction pattern are consistent with space group C2. The presence of two molecules in the asymmetric unit with a molecular weight of ,12.2,kDa gives a crystal volume per protein mass (VM) of ,3.1,Å3,Da,1 and a solvent content of ,60% by volume. [source] Structural comparison of Escherichia colil -asparaginase in two monoclinic space groupsACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2003Mario Sanches The functional l -asparaginase from Escherichia coli is a homotetramer with a molecular weight of about 142,kDa. The X-ray structure of the enzyme, crystallized in a new form (space group C2) and refined to 1.95,Å resolution, is compared with that of the previously determined crystal form (space group P21). The asymmetric unit of the new crystal form contains an l -asparaginase dimer instead of the tetramer found in the previous crystal form. It is found that crystal contacts practically do not affect the conformation of the protein. It is shown that subunit C of the tetrameric form is in a conformation which is systematically different from that of all other subunits in both crystal forms. Major conformational differences are confined to the lid loop (residues 14,27). In addition, the stability of this globular protein is analyzed in terms of the interactions between hydrophobic parts of the subunits. [source] Crystallization and preliminary X-ray analysis of NADP(H)-dependent alcohol dehydrogenases from Saccharomyces cerevisiae and Rana pereziACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2003Eva Valencia Different crystal forms diffracting to high resolution have been obtained for two NADP(H)-dependent alcohol dehydrogenases, members of the medium-chain dehydrogenase/reductase superfamily: ScADHVI from Saccharomyces cerevisiae and ADH8 from Rana perezi. ScADHVI is a broad-specificity enzyme, with a sequence identity lower than 25% with respect to all other ADHs of known structure. The best crystals of ScADHVI diffracted beyond 2.8,Å resolution and belonged to the trigonal space group P3121 (or to its enantiomorph P3221), with unit-cell parameters a = b = 102.2, c = 149.7,Å, , = 120°. These crystals were produced by the hanging-drop vapour-diffusion method using ammonium sulfate as precipitant. Packing considerations together with the self-rotation function and the native Patterson map seem to indicate the presence of only one subunit per asymmetric unit, with a volume solvent content of about 80%. ADH8 from R. perezi is the only NADP(H)-dependent ADH from vertebrates characterized to date. Crystals of ADH8 obtained both in the absence and in the presence of NADP+ using polyethylene glycol and lithium sulfate as precipitants diffracted to 2.2 and 1.8,Å, respectively, using synchrotron radiation. These crystals were isomorphous, space group C2, with approximate unit-cell parameters a = 122, b = 79, c = 91,Å, , = 113° and contain one dimer per asymmetric unit, with a volume solvent content of about 50%. [source] Crystallization and preliminary X-ray analysis of bucain, a novel toxin from the Malayan krait Bungarus candidusACTA CRYSTALLOGRAPHICA SECTION D, Issue 10-2 2002L. Watanabe Bucain is a three-finger toxin, structurally homologous to snake-venom muscarinic toxins, from the venom of the Malayan krait Bungarus candidus. These proteins have molecular masses of approximately 6000,8000,Da and encompass the potent curaremimetic neurotoxins which confer lethality to Elapidae and Hydrophidae venoms. Bucain was crystallized in two crystal forms by the hanging-drop vapour-diffusion technique in 0.1,M sodium citrate pH 5.6, 15% PEG 4000 and 0.15,M ammonium acetate. Form I crystals belong to the monoclinic system space group C2, with unit-cell parameters a = 93.73, b = 49.02, c = 74.09,Å, , = 111.32°, and diffract to a nominal resolution of 1.61,Å. Form II crystals also belong to the space group C2, with unit-cell parameters a = 165.04, b = 49.44, c = 127.60,Å, , = 125.55°, and diffract to a nominal resolution of 2.78,Å. The self-rotation function indicates the presence of four and eight molecules in the crystallographic asymmetric unit of the form I and form II crystals, respectively. Attempts to solve these structures by molecular-replacement methods have not been successful and a heavy-atom derivative search has been initiated. [source] Crystallization and preliminary X-ray analysis of the selenate reductase from Thauera selenatisACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2002Megan J. Maher Selenate reductase from Thauera selenatis was crystallized using ammonium sulfate as a precipitant. Crystals of selenate reductase belong to the space group C2, with unit-cell parameters a = 116.9, b = 67.5, c = 186.7,Å, , = 90°. Native data to 2.1,Å resolution have been collected and a heavy-atom derivative has been identified following soaking of the crystals in a solution of trimethyl lead acetate. [source] Purification, crystallization and preliminary characterization of an Eph-B2/ephrin-B2 complexACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2002Juha-P. Eph receptors and their ephrin ligands are involved in various aspects of cell,cell communication during development, including those of the axon pathfinding processes in the nervous system and cell,cell interactions of the vascular endothelial cells. The recognition and binding properties of the ligand-binding domain of EphB2 receptor and the extracellular domain of ephrin-B2 have been studied and two different cocrystals of their complex have been generated. One crystal form has space group C2, diffracts to 3.5,Å and has unit-cell parameters a = 128, b = 88, c = 79,Å, , = 112°. The other crystal form grows in space group P1, has unit-cell parameters a = 78, b = 78, c = 78,Å, , = 69, , = 75, , = 69° and diffracts to 2.7,Å. Structure-determination experiments using the latter form are in progress. The structure of the complex will elucidate the chemical nature of the interactions between Eph receptors and ephrins, which would create the possibility of using them as targets for structure-based anticancer-drug development. [source] Destabilizing effect of a fluorouracil extra base in a hybrid RNA duplex compared with bromo and chloro analoguesACTA CRYSTALLOGRAPHICA SECTION D, Issue 11 2001William Cruse In the presence of cobalt, rhodium or iridium hexammine salts, the RNA/DNA hybrid r-GCUUCGGC-dXU (with X = F, Cl or Br) crystallizes as a double-stranded helix with four consecutive G,U and C,U mismatches. The deoxy chloro- and bromouracil derivatives are isomorphous, space group C2, unit-cell parameters a = 53.80, b = 19.40, c = 50.31,Å, , = 109.9°, with the same infinite helix arrangement in the packing along the c axis with one extra DNA halogenouracil base included in the stacking. However, the fluorouracil derivative, with unit-cell parameters a = 53.75, b = 19.40, c = 45.84,Å, , = 105.7°, is not isomorphous. The corresponding extra DNA base dFU of the second strand is ejected out of the helical stack, leading to a shortening of the c axis. The specific destabilization of the fluorouracil for the duplex building is analyzed in terms of the polarization effect of the halogen atom attached to the 3,-terminal base that modulates its interactions. [source] Crystallization and preliminary X-ray analysis of a thermoalkalophilic lipase from Bacillus stearothermophilus L1ACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2001Seong-Tae Jeong A thermoalkalophilic lipase from Bacillus stearothermophilus L1 (L1 lipase) was crystallized in two different crystal forms using a low concentration of the enzyme and a calcium-exchange process. The first, needle-like, crystal form, which diffracts to about 3.5,Å, belongs to the orthorhombic space group P212121, with unit-cell parameters a = 67.84, b = 72.96, c = 104.41,Å. The second, monoclinic, crystal form, which behaves better than the first form for crystallographic analyses, belongs to the monoclinic space group C2 and has unit-cell parameters a = 119.62, b = 85.05, c = 98.36,Å, , = 99.73°. From the monoclinic crystals, a native data set and a samarium-derivative data set were collected to 2.0 and 2.3,Å resolution, respectively. The difference Patterson map between the two data sets shows strong heavy-atom peaks, indicating that the crystals are suitable for a high-resolution structure determination. [source] Crystallization and preliminary X-ray crystallographic studies of recombinant human betaine,homocysteine S-methyltransferaseACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2001Nandita Bose Betaine,homocysteine S-methyltransferase (BHMT) catalyzes a reaction essential for regulation of methionine and homocysteine metabolism and the catabolism of choline in mammalian tissues. Human recombinant BHMT (MW = 45,kDa) has been crystallized by the hanging-drop vapor-diffusion method at 294,K using ethylene glycol as the precipitant. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 109.190, b = 91.319, c = 88.661,Å, , = 122.044°, and diffract to 2.9,Å resolution on a local rotating-anode X-ray source. Rotation-function analysis and the Matthews coefficient, VM = 2.46,Å3,Da,1, are consistent with a dimer in the asymmetric unit, suggesting that the active enzyme is a tetramer with 222 symmetry. [source] Preliminary crystallographic studies of an extremely thermostable KDG aldolase from Sulfolobus solfataricusACTA CRYSTALLOGRAPHICA SECTION D, Issue 11 2000Elaine J. Hendry Crystals have been grown of 2-keto-3-deoxygluconate aldolase (KDG aldolase) from the hyperthermophilic archaeon Sulfolobus solfataricus that diffract to 2.2,Å resolution. The enzyme catalyses the reversible aldol cleavage of 2-keto-3-dexoygluconate to pyruvate and glyceraldehyde, the third step of a modified non-phosphorylated Entner,Doudoroff pathway of glucose oxidation. S. solfataricus grows optimally at 353,K and the enzyme itself has a half-life of 2.5,h,at 373,K. Knowledge of the crystal structure of KDG aldolase will further understanding of the basis of protein hyperthermostability and create a target for site-directed mutagenesis of active-site residues, with the aim of altering substrate specificity. Three crystal forms have been obtained: orthorhombic crystals of space group P212121, which diffract to beyond 2.15,Å, monoclinic crystals of space group C2, which diffract to 2.2,Å, and cubic crystals of space group P4232, which diffract to 3.4,Å. [source] Crystallization and preliminary X-ray analysis of the matrix protein from Ebola virusACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2000Andréa Dessen The matrix protein from Ebola virus is a membrane-associated molecule that plays a role in viral budding. Despite its functional similarity to other viral matrix proteins, it displays no sequence similarity and hence may have a distinct fold. X-ray diffraction quality crystals of the Ebola VP40 matrix protein were grown by the hanging-drop vapour-diffusion method. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 64.4, b = 91.1, c = 47.9,Å, , = 96.3°. A data set to 1.9,Å resolution has been collected using synchrotron radiation. The unit cell contains one molecule of molecular weight 35,kDa per asymmetric unit, with a corresponding volume solvent content of 35%. [source] Crystallization and preliminary X-ray diffraction studies of d(ACGTAGCTACGT)2:[actinomycin D, (echinomycin)2] and d(ACGTAGCTACGT)2:[actinomycin D, (triostin A)2] complexesACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2000Hana L. Takusagawa A DNA,multiple drug complex, d(ACGTAGCTACGT)2:[actinomycin D, (echinomycin)2] has been crystallized. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 85.6, b = 72.8, c = 56.6,Å, , = 101.5° at 93,K and Z = 8.,The crystal diffracted to 3.0,Å resolution along the DNA fiber axis and to 3.5,Å resolution in other directions. The Patterson maps indicate that all complexes in the crystal are oriented along their helical axes in the [10] direction. [source] Crystallization and preliminary X-ray crystallographic analysis of the ArsM arsenic(III) S -adenosylmethionine methyltransferaseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2010Kavitha Marapakala Arsenic is the most ubiquitous environmental toxin and carcinogen and consequently ranks first on the Environmental Protection Agency's Superfund Priority List of Hazardous Substances. It is introduced primarily from geochemical sources and is acted on biologically, creating an arsenic biogeocycle. A common biotransformation is methylation to monomethylated, dimethylated and trimethylated species. Methylation is catalyzed by the ArsM (or AS3MT) arsenic(III) S -adenosylmethionine methyltransferase, an enzyme (EC 2.1.1.137) that is found in members of every kingdom from bacteria to humans. ArsM from the thermophilic alga Cyanidioschyzon sp. 5508 was expressed, purified and crystallized. Crystals were obtained by the hanging-drop vapor-diffusion method. The crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 84.85, b = 46.89, c = 100.35,Å, , = 114.25° and one molecule in the asymmetric unit. Diffraction data were collected at the Advanced Light Source and were processed to a resolution of 1.76,Å. [source] Crystallization and preliminary X-ray analysis of the major peanut allergen Ara,h,1 core regionACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2010Cerrone Cabanos Peanuts contain some of the most potent food allergens known to date. Ara,h,1 is one of the three major peanut allergens. As a first step towards three-dimensional structure elucidation, recombinant Ara,h,1 core region was cloned, expressed in Escherichia coli and purified to homogeneity. Crystals were obtained using 0.1,M sodium citrate pH 5.6, 0.1,M NaCl, 15% PEG 400 as precipitant. The crystals diffracted to 2.25,Å resolution using synchrotron radiation and belonged to the monoclinic space group C2, with unit-cell parameters a = 156.521, b = 88.991, c = 158.971,Å, , = 107.144°. Data were collected at the BL-38B1 station of SPring-8 (Hyogo, Japan). [source] Crystallization and preliminary X-ray diffraction analysis of Pseudomonas aeruginosa phosphorylcholine phosphataseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 8 2010Lisandro H. Otero Pseudomonas aeruginosa phosphorylcholine phosphatase (PchP) catalyzes the hydrolysis of phosphorylcholine to produce choline and inorganic phosphate. Phosphorylcholine is released by the action of haemolytic phospholipase C (PlcH) on phosphatidylcholine or sphingomyelin. PchP belongs to the HAD superfamily and its activity is dependent on Mg2+, Zn2+ or Cu2+. The possible importance of PchP in the pathogenesis of P. aeruginosa, the lack of information about its structure and its low identity to other members of this family led us to attempt its crystallization in order to solve its three-dimensional structure. Crystals of the protein have been grown and diffraction data have been obtained to 2.7,Å resolution. The crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 137.16, b = 159.15, c = 73.31,Å, , = 117.89°. Statistical analysis of the unit-cell contents and the self-rotation function suggest a tetrameric state of the molecule with 222 point-group symmetry. [source] Structure of the newly found green turtle egg-white ribonucleaseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2010Somporn Katekaew Marine green turtle (Chelonia mydas) egg-white ribonuclease (GTRNase) was crystallized from 1.1,M ammonium sulfate pH 5.5 and 30% glycerol using the sitting-drop vapour-diffusion method. The structure of GTRNase has been solved at 1.60,Å resolution by the molecular-replacement technique using a model based on the structure of RNase 5 (murine angiogenin) from Mus musculus (46% identity). The crystal belonged to the monoclinic space group C2, with unit-cell parameters a = 86.271, b = 34.174, c = 39.738,Å, , = 90, , = 102, , = 90°. GTRNase consists of three helices and seven ,-strands and displays the ,+, folding topology typical of a member of the RNase A superfamily. Superposition of the C, coordinates of GTRNase and RNase A superfamily members indicates that the overall structure is highly similar to that of angiogenin or RNase 5 from M. musculus (PDB code 2bwl) and RNase A from Bos taurus (PDB code 2blz), with root-mean-square deviations of 3.9 and 2.0,Å, respectively. The catalytic residues are conserved with respect to the RNase A superfamily. The three disulfide bridges observed in the reptilian enzymes are conserved in GTRNase, while one further disulfide bond is required for the structural stability of mammalian RNases. GTRNase is expressed in egg white and the fact that its sequence has the highest similarity to that of snapping turtle pancreatic RNase suggests that the GTRNase secreted from oviduct cells to form egg white is probably the product of the same gene as activated in pancreatic cells. [source] Crystallization and preliminary X-ray crystallographic analysis of BxlA, an intracellular ,- d -xylosidase from Streptomyces thermoviolaceus OPC-520ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2010Hideaki Morioka BxlA from Streptomyces thermoviolaceus OPC-520, together with the extracellular BxlE and the integral membrane proteins BxlF and BxlG, constitutes a xylanolytic system that participates in the intracellular transport of xylan-degradation products and the production of xylose. To elucidate the mechanism of the hydrolytic degradation of xylooligosaccharides to xylose at the atomic level, X-ray structural analysis of BxlA was attempted. The recombinant BxlA protein (molecular weight 82,kDa) was crystallized by the hanging-drop vapour-diffusion method at 289,K. The crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 142.2, b = 129.5, c = 101.4,Å, , = 119.8°, and contained two molecules per asymmetric unit (VM = 2.47,Å3,Da,1). Diffraction data were collected to a resolution to 2.50,Å and provided a data set with an overall Rmerge of 8.3%. [source] Crystallization of community-acquired respiratory distress syndrome toxin from Mycoplasma pneumoniaeACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 3 2010Olga N. Pakhomova Community-acquired respiratory distress syndrome toxin (CARDS TX) is a 591-amino-acid protein with ADP-ribosyltransferase and vacuolating activities that damages the cells lining the respiratory tracts of patients infected with the bacterial pathogen Mycoplasma pneumoniae. Crystals of CARDS TX were grown in space group C2, with unit-cell parameters a = 191.4, b = 107.4, c = 222.1,Å, , = 90.6°. A complete 2.2,Å data set was obtained from a single CARDS TX crystal. [source] Crystallization and preliminary X-ray analysis of Na-SAA-2 from the human hookworm parasite Necator americanusACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2010Oluwatoyin A. Asojo Human hookworms are among the most pathogenic soil-transmitted helminths. These parasitic nematodes have co-evolved with the host and are able to maintain a high worm burden for decades without killing the human host. However, it is possible to develop vaccines against laboratory-challenge hookworm infections using either irradiated third-state infective larvae (L3) or enzymes from the adult parasites. In an effort to control hookworm infection globally, the Human Hookworm Vaccine Initiative, a product-development partnership with the Sabin Vaccine Institute to develop new control tools including vaccines, has identified a battery of protein antigens, including surface-associated antigens (SAAs) from L3. SAA proteins are characterized by a 13,kDa conserved domain of unknown function. SAA proteins are found on the surface of infective L3 stages (and some adult stages) of different nematode parasites, suggesting that they may play important roles in these organisms. The atomic structures and function of SAA proteins remain undetermined and in an effort to remedy this situation recombinant Na-SAA-2 from the most prevalent human hookworm parasite Necator americanus has been expressed, purified and crystallized. Useful X-ray data have been collected to 2.3,Å resolution from a crystal that belonged to the monoclinic space group C2 with unit-cell parameters a = 73.88, b = 35.58, c = 42.75,Å, , = 116.1°. [source] Purification, crystallization and preliminary X-ray diffraction analysis of Cif, a virulence factor secreted by Pseudomonas aeruginosaACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 1 2010Christopher D. Bahl The opportunistic pathogen Pseudomonas aeruginosa secretes a protein that triggers the accelerated degradation of the cystic fibrosis transmembrane conductance regulator (CFTR) in airway epithelial cells. This protein, which is known as the CFTR inhibitory factor (Cif), acts as a virulence factor and may facilitate airway colonization by P. aeruginosa. Based on sequence similarity Cif appears to be an epoxide hydrolase (EH), but it lacks several of the conserved features found in the active sites of canonical members of the EH family. Here, the crystallization of purified recombinant Cif by vapor diffusion is reported. The crystals formed in space group C2, with unit-cell parameters a = 167.4, b = 83.6, c = 88.3,Å, , = 100.6°. The crystals diffracted to 2.39,Å resolution on a rotating-anode source. Based on the calculated Matthews coefficient (2.2,Å3,Da,1), it appears that the asymmetric unit contains four molecules. [source] Crystallization and preliminary X-ray diffraction data analysis of stenodactylin, a highly toxic type 2 ribosome-inactivating protein from Adenia stenodactylaACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 1 2010Giovanna Tosi Ribosome-inactivating proteins (RIPs) inhibit protein synthesis and induce cell death by removing a single adenine from a specific rRNA loop. They can be divided into two main groups: type 1 and type 2 RIPs. Type 1 RIPs are single-chain enzymes with N-glycosidase activity. Type 2 RIPs contain two chains (A and B) linked by a disulfide bond. The A chain has RIP enzymatic activity, whereas the B chain shows lectin activity and is able to bind to glycosylated receptors on the cell surface. Stenodactylin is a type 2 RIP from the caudex of Adenia stenodactyla from the Passifloraceae family that has been recently purified and characterized. It shows a strong enzymatic activity towards several substrates and is more cytotoxic than other toxins of the same type. Here, the crystallization and preliminary X-ray diffraction data analysis of stenodactylin are reported. This RIP forms crystals that diffract to high resolution (up to 2.15,Å). The best data set was obtained by merging data collected from two crystals. Stenodactylin crystals belonged to the centred monoclinic space group C2 and contained two molecules in the asymmetric unit. [source] Crystallization and preliminary X-ray diffraction studies of the carbohydrate-recognition domain of SIGN-R1, a receptor for microbial polysaccharides and sialylated antibody on splenic marginal zone macrophagesACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 12 2009Noella Silva-Martin SIGN-R1, or CD209b, is a mouse C-type lectin receptor that is expressed at high levels on macrophages in lymphoid tissues, especially within the marginal zone of the spleen. SIGN-R1 can bind and mediate the uptake of various microbial polysaccharides, including dextrans, lipopolysaccharides and pneumococcal capsular polysaccharides. It has been shown that SIGN-R1 mediates the clearance of encapsulated pneumococcus, complement fixation via binding C1q independent of antibody and innate resistance to pneumococcal infection. Recently, SIGN-R1 has also been demonstrated to bind sialylated antibody and mediate its activity to suppress autoimmunity. The carbohydrate-recognition domain (CRD) of SIGN-R1 has been cloned and overexpressed in a soluble secretory form in mammalian Chinese hamster ovary (CHO) cells. The CRD protein of SIGN-R1 was purified from CHO cell-culture supernatant and concentrated for crystallization using the hanging-drop vapour-diffusion method at 291,K. Crystals grew from a mixture of 2,M ammonium sulfate in 0.1,M bis-tris pH 5.5. Single crystals, which belonged to the monoclinic space group C2 with unit-cell parameters a = 146.72, b = 92.77, c = 77.06,Å, , = 121.66°, allowed the collection of a full X-ray data set to a maximum resolution of 1.87,Å. [source] | ||||||||||