共查询到20条相似文献,搜索用时 31 毫秒
1.
Shigehiro Kamitori Tomoya Satou Takashi Tonozuka Yoshiyuki Sakano Hiroshi Matsuzawa Kenji Okuyama 《Journal of structural biology》1995,114(3)
Crystals of Thermoactinomyces vulgaris α-amylase II, which is a new type of α-amylase having hydrolysis activities for pullulan and cyclodextrins, have been obtained and diffraction data to 2.9 Å resolution were collected. The crystal belongs to an orthorhombic system with cell dimensions of a = 119.5 Å, b = 120.6 Å, and c = 114.6 Å and a space group of P 212121. Two or three protein molecules are expected to exist in an asymmetric unit. 相似文献
2.
Tadaaki Kishi Masato Kato Toshiyuki Shimizu Keiko Kato Kazumasa Matsumoto Shigetaka Yoshida Sadao Shiosaka Toshio Hakoshima 《Journal of structural biology》1997,118(3):248-251
Neuropsin (Mr25 032) is a serine protease expressed in the limbic system of mouse brain. It has been implicated in various neurological processes including formation of memory and may be important as a drug target in the treatment of epilepsy. The recombinant protein was produced using a baculovirus expression system and was purified. Two crystal forms were obtained by a hanging-drop vapor-diffusion method with polyethylene glycol. Preliminary X-ray crystallographic analysis revealed that crystal form I belongs to triclinic space groupP1 with unit cell dimensionsa= 97.16 Å,b= 97.12 Å,c= 46.75 Å and α = 99.17°, β = 99.77°, γ = 117.35°. Self-rotation function analysis of these data of form I indicates the position of a noncrystallographic threefold axis. There are six molecules in the crystallographic asymmetric unit. Crystal form II also belongs to triclinic space groupP1 but has unit cell dimensions ofa= 38.40 Å,b= 55.16 Å,c= 65.37 Å and α = 95.38°, β = 89.98°, γ = 110.46° with two molecules in the crystallographic asymmetric unit. Form II has a noncrystallographic twofold axis. Intensity data to 3.1 Å resolution for form I and to 2.2 Å resolution for form II have been collected. 相似文献
3.
Timothy L. Bullock G. Parthasarathy Karen L. King Helen M. Kent Thomas M. Roberts Murray Stewart 《Journal of structural biology》1996,116(3):432-437
We have obtained two new crystal forms of theAscarismajor sperm protein (MSP) that mediates amoeboid cell motility in nematode sperm. We obtained crystals with C2 symmetry from bacterially expressed α-MSP witha= 216.5 Å,b= 38.6 Å,c= 32.5 Å, γ = 93.1° and also crystals with P21symmetry from native β-MSP witha= 63.1 Å,b= 91.7 Å,c= 72.5 Å, γ = 91.3°. A full native data set has been collected for each crystal form using synchrotron radiation. Both crystal forms diffract to 2 Å and are suitable for high-resolution structural investigation. 相似文献
4.
The compound (HOCH2CH2S)
) (1) has been prepared by the reaction of antimony(III) isopropoxide and 2-mercaptoethanol in a 1:2 molar ratio. Reaction of 1 with MOCH3 (where M = Li, Na and K) yields bimetallic products of the type, M[(OCH2CH2S)
)]. All these derivatives have been characterized by elemental analysis, IR, NMR (1H and 13C) spectra and molar conductivity measurements. Crystals of 1 are triclinic, space group P
, with a = 6.449(2), b = 10.285(2), c = 13.494(1) Å, α = 78.08(1), β = 75.99(1), γ = 71.54(2)°, V = 815.48 Å3, Z = 4, Dcalc = 2.239 g cm−3, (Mo Kα) λ = 0.7107 Å, μ = 3.55 mm−1, F(000) = 528, T = 295 K, final R = 0.0189 for 2344 reflections. One of the two mercaptoethanol moieties in 1 forms a five-membered chelate ring with antimony, Sb(1)---O(11) = 2.023(2) Å and Sb(1)---S(11) = 2.434(1) Å, while the other is bonded through the S atom only, Sb(1)---S(12) = 2.434(1) Å. The angles between these primary bonds with a mean value of 90.2° suggest a basically pyramidal, or pseudo tetrahedral structure if the stereochemically active lone pair is included in the coordination sphere. Two molecules are linked by intermolecular hydrogen bridges. The presence of weak intermolecular secondary bonding, Sb(1)---O(12) = 2.567(3) Å, in the complex indicates that the overall coordination polyhedron is best described in terms of a distorted trigonal bipyramidal arrangement. 相似文献
5.
The Borrelia burgdorferi outer surface lipoprotein OspA is a current focus for vaccine development to prevent Lyme disease infection. A soluble, recombinant form of the protein lacking the aminoterminal lipid membrane anchor was cocrystallized with the Fab fragment of an agglutinating mouse monoclonal antibody. The crystals belong to space group P212121, with a = 90.0 Å, b = 91.9 Å, and c = 102.9 Å and they were found to diffract to a maximum resolution of 2.8 Å using synchrotron radiation. 相似文献
6.
Three-dimensional, single-crystal, X-ray diffraction methods were used to determine the structure of the calcium chloride complex of α-d-allopyranosyl α-d-allopyranoside. The crystal is monoclinic with cell dimensions: a = 16.262(5), b = 8.345(5), c = 8.298(5)Å, β = 98.428(5)Å, and z = 2. The space group is P21. The structure was solved by three-dimensional Patterson and Fourier methods, and was refined by least-squares techniques to give a conventional discrepancy factor of R = 0.026; 2435 diffractometer-read reflections were used. The cation was found to be in 9-fold co-ordination to O-1, O-2, O-3, O-2′, O-3′, and four water molecules. 相似文献
7.
Bis(pentamethylcyclopentadienyl)samarium bis- (tetrahydrofuranate), (C5Me5)2Sm(THF)2, reacts with 2,3,5,6-tetramethylphenol in toluene to yield (C5Me5)2Sm(OC6HMe4-2,3,5,6). The compound crystallizes in the space group P21/c with a = 8.725(3) Å, b=18.821(6) Å, c=18.461(6) Å, β= 111.17(2)°, V = 2827(2) Å3 and Dc=1.340 g cm−3 for Z = 4. Molecules of the aryloxide complex are monomeric and exhibit a bent metallocene structure with a nearly linear Sm---O---C(aryloxide) linkage: Sm---O = 2.13(1) Å, O---C = 1.29(2) Å, and Sm---O---C = 172.3(13)°. Reaction of the samarium complex with phenyllithium produces the previously- characterized species (C5Me5)2Sm(C6H5)(THF). 相似文献
8.
Eric S. Raper 《Inorganica chimica acta》1991,180(2)
1-Methylimidazoline-2(3H)-thione (mimtH) and copper(I) thiocyanate in refluxing ethanolacetonitrile produce a colourless, diamagnetic complex, [Cu2(mimtH)4(SCN)2], which crystallises in an orthorhombic cell (a=8.0724(3), b=15.9545(6), c=21.3357(8) Å), space GROUP=Pbca, Z=4, final R=0.0319 from 2427 observed reflections F>4σc(F)). In the dimeric complex the copper(I) atoms are pseudo-tetrahedrally coordinated by pairs of, respectively, asymmetrically μ2-S bridging mimtH, terminal monodentate-S mimtH, (Cu---S=2.290(1) Å), and terminal monodentate-S thiocyanate, (Cu---S=2.332(1) Å). Each pair of ligands is trans-related to its partner across crystallographic centres of symmetry, consequently, each copper(I) atom has an identical S4 donor set with angles at the metal ranging from 95.9(1)° to 121.8(1)°. The centro-symmetric Cu2S2 core is rhomboid with Cu---S=2.377(1) and 2.457(1) Å, Cu---Sbr---Cu=72.6(1)° and Cu---Cu, Sbr---Sbr separation distances of 2.861(1) and 3.897(2) Å, respectively. Thermal decomposition of the complex in flowing air, (133–1000 °C), involves de-sulfurisation of mimtH and thiocyanate with concomitant production of copper(II) sulfide followed by oxidation to copper(II) oxide. 相似文献
9.
The crystal structure of 1,6-anhydro-β-d-mannopyranose, C6H10O5, is orthorhombic, P212121, with a = 10.971(2), b = 13.935(3), c = 9.012(1) Å, V = 1377.76 »3 (MoKα, λ = 0.7107 Å), Z = 8, Dx = 1.563 M.gm−3, Dm = 1.565 M.gm−3. the structure was solved by MULTAN and refined to R(F) = 0.043 for 2355 reflections. The two symmetry-independent molecules in the unit cell have similar conformations, except for the orientation of one of the three hydroxyl groups. The conformation of the pyranose rings is 1C4 distorted towards Eo, and that of the anhydro rings is E. There are significant differences between the two molecules in two of the four C---O bond-lengths. These occur where there are important differences in the hydrogen-bonding environment of the oxygen atoms. The molecules are hydrogen-bonded by three linear and three bifurcated O---H···O interactions which form four-membered loops linked into infinite chains. Empirical force-field calculations with MMI-CARB reproduced the geometry of the molecules within the variations observed experimentally between the two molecules, except for a C---O bond in one of the molecules. The effect of excluding the anomeric effect from the theoretical calculations was not significant. Calculations for an intramolecularly hydrogen-bonded molecule were also carried out as a model for the molecules in a non-polar solvent. 相似文献
10.
Shwu-Huey Liaw Hsin-Zu Chen I-Chun Kuo Kaw-Yan Chua 《Journal of structural biology》1998,123(3):265-268
Crystals of the 14-kDa group 5 allergen fromDermatophagoides pteronyssinus(Der p 5) have been obtained at low pH and diffract to 3-Å resolution using a conventional x-ray source. The crystals belong to tetragonal space group P41212 or P43212, with unit cell parametersa=b= 114 Å andc= 234 Å. A self-rotation search revealed a 432 point symmetry and thus suggested 96 molecules in one unit cell, hence 12 monomers in each asymmetric unit. 相似文献
11.
Thomas C. Diller Nguyen-Huu Xuong Susan S. Taylor 《Protein expression and purification》2000,20(3):357
To elucidate the structural basis for important differences between types I and II regulatory subunit isoforms (RI and RII) of adenosine 3′,5′-cyclic monophosphate (cAMP)-dependent protein kinase, the full-length RIIβ isoform and five RIIβ deletion mutants were constructed, expressed, purified, and screened for crystallization. Only one of these six proteins yielded diffraction quality crystals. Crystals were grown of the RIIβ deletion mutant (Δ1–111) monomer potentially in complex with two cAMP molecules. X-ray diffraction quality data were obtained only after significant modification to existing purification procedures. Modifications required a Sepharose, not agarose, support for cAMP affinity chromatography followed by rapid, quantitative removal of free cAMP by size-exclusion chromatography under reducing conditions. Data to 2.4 Å resolution were collected at 29°C using synchrotron radiation on a single crystal measuring 0.2 × 0.3 × 1.2 mm3. Data were 99% complete. The hexagonal crystal belonged to space group P6(1) or P6(5) with unit cell dimensions a = b = 161.62 Å and c = 39.66 Å. 相似文献
12.
John C. Sinclair Rupika Delgoda Martin E.M. Noble Sarah Jarmin Ngee K. Goh Edith Sim 《Protein expression and purification》1998,12(3):371-380
TheN-hydroxyarylamineO-acetyltransferase fromSalmonella typhimuriumhas been expressed as a histidine-tagged fusion protein inEscherichia coliand purified to apparent homogeneity using single-step immobilized metal ion chromatography. Sufficient quantities of the purified protein have been obtained to allow its characterization by physical methods including dynamic light scattering and electrospray mass spectrometry. The substrate specificity and temperature sensitivity of the enzymatic activity have also been assessed. The enzyme has been crystallized from sodium, potassium tartrate and X-ray diffraction data have been obtained to allow the identification of an orthorhombic unit cell, point group P21212, with dimensionsa= 137 Å,b= 223 Å, andc= 105 Å. These crystals will provide a route to a crystallographic determination of the structure of the protein. 相似文献
13.
Crystal structures of cyclomaltohexaose (α-cyclodextrin) complexes with p-chlorophenol and p-cresol have been determined by single-crystal X-ray diffraction studies. The space group of the α-cyclodextrin–p-chlorophenol complex is P212121 with unit cell dimensions of a=15.299(3), b=24.795(5), c=13.447(5) Å, and that of the α-cyclodextrin–p-cresol complex is P21 with unit cell dimensions of a=7.927(7), b=13.568(7), c=24.54(1) Å, β=90.41(8)°. In spite of the similar structures of guest molecules, both complexes have different inclusion modes and packing structures. 相似文献
14.
Alicia Guasch Antonio Parrga Joan Pous Jos M. Valpuesta Jos L. Carrascosa Miquel Coll 《FEBS letters》1998,430(3)
The connector or portal particle from double-stranded DNA bacteriophage φ29 has been crystallized. This structure, which connects the head of the virus with the tail and plays a central role in prohead assembly and DNA packaging and translocation, is formed by 12 subunits of the p10 protein and has a molecular weight of 430 kDa. The connector structure was proteolysed with endoproteinase Glu-C from Staphylococcus aureus V8, which removes 13 and 18 amino acids from the amino- and carboxy-terminal regions of the p10 protein, respectively. Two crystal forms were grown from drops containing an alcohol solution and paraffin oil. Crystals of form I are monoclinic, space group C2 with cell dimensions a=416.86 Å, b=227.62 Å, c=236.68 Å and β=96.3° and contain four connector particles per asymmetric unit. Crystals of form II are tetragonal, space group P42212 with cell dimensions a=b=170.2 Å, c=156.9 Å and contain half a particle per asymmetric unit. X-ray diffraction data from both native crystal forms have been collected to 6.0 and 3.2 Å respectively, using synchrotron radiation. Crystals of form II are likely to have the same packing arrangement as the two-dimensional crystals analyzed previously by electron microscopy. 相似文献
15.
George T. DeTitta James W. Edmonds William L. Duax 《Prostaglandins & other lipid mediators》1975,9(5):659-665
The molecular conformation of the monoclinic crystalline polymorph of prostaglandin A1 has been determined by X-ray diffraction techniques. The space group is P21 with a = 13.637 (2), b = 7.567 (1), I c = 10.576 (2) Å, β = 107.37 (3)°; Dc = 1.073 g·cm−3 for Z = 2. The molecular conformation is characterized by the nearly parallel arrangement of the C1–C7 and C13–C20 side chains, with a general flattening of the overall structure when compared with the orthorhombic polymorph. The cyclopentenone moiety assumes a C8 envelope conformation with C8 and O9 displaced +0.29 Å and −0.18 Å from the C9–C10=C11–C12 plane respectively. Concerted, small variations of the torsion angles, primarily about the C8–C12, C14–C15 and C16–C17 bonds, bring the monoclinic and orthorhombic conformations into coincidence. 相似文献
16.
Zhi-Dong Xu He Liu Su-Long Xiao Ming Yang Xian-He Bu 《Journal of inorganic biochemistry》2002,90(3-4)
The complex [Mn(L)(NO3)2(H2O)2] (1) (L=2H-5-hydroxy-1,2,5-oxadiazo[3,4-f]1,10-phenanthroline) was synthesized and characterized by elemental analysis, IR and UV. The crystal and molecular structure of 1 was determined by single-crystal X-ray diffraction; crystal data: light yellow, monoclinic, space group P21/n, Z=4, a=7.432(2) Å, b=9.582(3) Å, c=23.445(7) Å, β=90.519(5)°. The Mn atom in 1 is hexa-coordinated in a distorted octahedral arrangement by two N atoms of the ligand L and four O atoms of two water molecules and two nitrate anions. Biological tests in vitro showed that 1 has significant antitumor activity against HL-60, KB, Hela and BGC-823 cells. The interaction of 1 with calf thymus DNA was investigated by absorption titration, thermal denaturation and viscosity measurements. The results suggest that 1 binds with DNA by intercalating via the ligand L. 相似文献
17.
X-ray crystal analyses of divalent copper, cobalt and calcium complexes of monoanionic (3-hydroxy-5-(hydroxymethyl)-2-methylisonicotinic acid) 5-phosphate (L1C8H9NO7P−) revealed the chemical compositions of Cu
---L·3H2O(1), Co
---L·5H2O(2) and Ca·L2·7H2O (3) and the coordination structures which depend on the coordination abilities and chemical properties of the respective metal ions. Although 1 and 2 crystals showed similar features, i.e., presence of the metal ion at the crystallographic center of symmetry and octahedral six-coordination, the patterns of coordination with the ligand molecules differed. While direct coordination to the L carboxyl oxygen was observed in 1 crystals, all ligation positions in 2 crystals were occupied by water molecules. On the other hand, 3 crystals formed a pentagonal bipyramidal structure (seven-coordination), where oxygens of L phosphates and water molecules coordinated to the calcium ion. Each of the complex structures showed characteristic molecular packing depending on the pattern of coordination to the respective metal ion. L is monoanionic in all complex crystals, where the phosphate and carboxyl groups are deprotonated and pyridine nitrogen is protonated, and is neutralized by each metal ion. Crystal data: 1, monoclinic, space group P21/c, A = 5.4129(6), B = 10.515(2), C = 22.770(2) Å, β = 91.853(9)°, Z = 4, R = 0.0404 for 1834 observed reflections; 2, triclinic, space group
, c = 6.789(3) Å, α = 96.84(3), β = 109.10(3), γ = 100.50(2)°, Z = 2, R = 0.0684 for 1605 observed reflections; 3, triclinic,
, a = 10.069(2), B = 14.501(3), c = 10.051(1) Å, α = 100.75(1), β = 97.28(2), γ = 76.18(2)°, Z = 2, R = 0.0540 for 3637 observed reflections. 相似文献
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18.
Vito Di Noto Roberto Zannetti Silvano Bresadola Antonio Marigo Carla Marega 《Inorganica chimica acta》1991,190(2)
The reaction of α-MgCl2 with boiling ethyl acetate affords MgCI2(CH3COOC2H5)2·
(CH3COOC2H5), which is obtained as crystals suitable for X-ray analysis only from the mother liquor. M=315.5, orthorhombic, space group P21221 (No. 18), a=25.077(3), b=8.616(1), c=7.345(1) Å, V=1587.0(3) Å3, Z=4, Dx=1.32 g cm−3,λ A(Mo Kα)=0.71069 Å, μ=4.17 cm−1, F(000)=664, T=298 K, observed reflections: 1667, R=0.059 and Rw=0.069. The structure is composed of polymeric chains of MgCl2(CH3COOC2H5)2 and the ethyl acetate molecules occupy a mutually trans position. 相似文献
19.
Structural analysis of 6-S-(benzoxazol-2-yl)-6-deoxy
Miles T. Lakin Nadine Mouhous-Riou Christelle Lorin Patrick Rollin Jan Kroon Serge Prez 《Carbohydrate research》1996,290(2)
The conformational behaviour of a representative azaheterocycle/thiosugar hybrid:
, 1, has been characterised by X-ray crystallography, molecular modelling and NMR studies. The crystal of 1 (C19H23NO6S) belongs to the monoclinic space group P21, with α = 8.4330(4), B = 10.287(3), C = 11.417(4) Å, β = 101.66(5)°, V = 970.0(5) Å3, and Z = 2. The structure has been determined by X-ray diffraction at 299 K using an area detector. Least-squares refinement based on 2352 reflections yielded a final wR2 of 0.098, with R1 = 0.040 [for 2210 reflections with Fo > 4σ(Fo)]. The pyranose ring adopts a conformation between that of the screw-boat, OS5, and the twist-boat, OT2 forms. Proton NMR chemical shifts have been assigned by measurement of ID and 2D spectra. The C-5-C-6 conformer populations in CDC13 solution have been estimated. In parallel, a 相似文献
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20.
The reactive palladium dimer, [Pd(dppm)(O2CCF3)]2, is carbonylated to [Pd(dppm)(O2CCF3)]2(μ-CO) in a reversible reaction with K = c. 7.2(2)x104 atm−1 (P1/2 = c. 2.4 Torr). This is significantly larger than is expected based on the λmax = 280 nm in the electronic spectrum. The product can be isolated in analytically pure form by crystallization under a CO atmosphere. It forms crystals in the monoclinic space group Cc with a = 18.584(5), b = 28.65(1), c = 11.164(3) Å and β = 95.16(2)°. The structure is significantly distorted. The bonding about the two palladium atoms is quite asymmetric. While one is close to a square planar geometry with a Pd---C(O) distance of 1.90(2) Å, the other is significantly pyramidalized and has a longer (2.00(2) Å) bond to the bridging CO. The Pd---Pd distance is only 2.896(2) Å, much shorter than that usually observed for formally non-bonded Pd atoms. 相似文献