首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Large single crystals of trimethylamine dehydrogenase, containing both [4Fe-4S]2+ centers and covalently bound FMN, have been prepared by the macro seeding technique. The crystals are monoclinic, space group P21 with cell parameters a = 147.63 A?, b = 71.96 A?, c = 83.66 A? and β = 97.64 °, and diffract to at least 2.0 Å resolution. There is one dimer of approximately 166,000 Mm per asymmetric unit. A 5.0 Å resolution anomalous scattering difference Patterson has been computed which shows the presence and position of two [4Fe-4S]2+ centers in the asymmetric unit. A self-rotation function computed at 6.0 Å resolution indicates a non-crystallographic 2-fold axis relating the two subunits. These results show trimethylamine dehydrogenase to be composed of two identical or very similar subunits each containing one [4Fe-4S]2+ center.  相似文献   

2.
A pencillin-sensitive enzyme, the exocellular dd-carboxypeptidase-transpeptidase from Streptomyces R61, has been crystallized from polyethylene glycol (Mr = 6000 to 7500) solution at pH 7·6. X-ray examination of the orthorhombic crystals shows the space group is P212121, with unit cell dimensions a = 51·1 A?, b = 67·4 A?, and c = 102·9 A?. With four molecules of molecular weight 38,000, the A?3/dalton ratio for the cell is 2·33. The crystals are stable to irradiation for 75 hours and are suitable for structure analysis to at least 2·4 Å resolution. The radius of gyration of the molecule in solution at pH 6.8 is 20.8 Å.  相似文献   

3.
The mitochondrial isoenzyme of aspartate aminotransferase (E.C. 2.6.1.1) has been isolated from chicken heart in an electrophoretically and immunologically homogeneous form. Large, well-diffracting single crystals of this enzyme, a dimeric molecule with a molecular weight of 90,000, have been grown by vapour phase diffusion against polyethylene glycol solutions. The crystals belong to space group P1. The unit cell, with the dimensions a = 55.6 A?, 6 = 58.7 A?, c = 76.0 A?, α = 85.3 °, β = 109.2 °, γ = 115.6 °, contains a single dimer. The diffraction pattern extends to at least 2.1 Å resolution.  相似文献   

4.
The crystals of ribonuclease St, the extracellular ribonuclease from Streptomyces erythreus, have been obtained from (NH4)2SO4 solution with acetate buffer (pH 4.1). The crystals belong to a monoclinic space group C2 with dimensions a = 88.4 A?, b = 33.0 A?, c = 69.0 A?, β = 98.4 °. There are two protein molecules per asymmetric unit. The crystals diffract beyond 2.0 Å resolution.  相似文献   

5.
Glutathione peroxidase prepared from bovine erythrocytes yields small, but well-ordered plate-like crystals. X-ray investigation shows them to belong to monoclinic space group C2. Unit cell dimensions are: a = 90.4 A?, b = 109.5 A?, c = 58.6 A?, β = 99 ° ± 15 min. The crystal density is ?c = 1.36 ± 0.02 g.cm?3. Consequently, the asymmetric unit of the crystal cell is occupied by one tetrameric molecule of Mr 84,000. Matthew's (1968) parameter ΓM is calculated to be 1.71 Å3/dalton.  相似文献   

6.
The lectin from the seeds of Abrus precatorius has been crystallized and the crystals subjected to study by X-ray diffraction and electron microscopy. Three closely related crystal forms were obtained, of orthorhombic space group P212121 with a = 138 A?, b = 142 A?, and c = 173 A?, of tetragonal space group P41212 with a = b = 136 A?, c = 176 A?, and a twinned intermediate of the first two. From electron microscopy and two-dimensional spatial filtering of electron micrographs of the crystals, the molecule appears to consist of four similar domains grouped in a roughly planar diamond-shaped arrangement having a local intramolecular dyad axis. The average diameter of the Abrus lectin molecule is 50 to 60 Å and the individual domains appear to have a diameter of about 25 Å.  相似文献   

7.
Reassembled alfalfa mosaic virus coat protein was partially digested with trypsin to remove the first 26 amino acids (Bol et al., 1974). These particles are empty icosahedral protein shells built with 60 alfalfa mosaic virus protein subunits. This aggregate has been crystallized in two different crystal forms, one of which diffracts X-rays to at least 3.4 Å resolution. The type I crystals (space group P63, a = 200 A?, c = 314 A?) contain two particles per cell separated by 195 Å with each sitting on a 3-fold axis. The type II crystals contain three particles per cell in space group P31or P32 (a = 201 A?, c = 485 A?). Other T = 1 viral particles have very similar diameters.  相似文献   

8.
Arc, a represser from Salmonella phage P22 has been crystallized from ammonium phosphate at pH 8.0. The crystals form in space group P212121 with a = 90.26 A?, b = 52.88 A? and c = 47.58 A?. The crystals diffract to 2.2 Å resolution.  相似文献   

9.
The “goose-type” lysozyme isolated from the egg-white of the black swan Cygnus atratus has been crystallized. The space group is P21 with one molecule of protein in the asymmetric unit. The cell parameters are a = 46.2 A?, b = 65.1 A?, c = 38.7 A?, β = 110 °. The crystals diffract to a resolution of 2.25 Å and a set of diffraction data for the native protein has been collected photographically.  相似文献   

10.
Crystals of triosephosphate isomerase (EC 5.3.1.1) from Trypanosoma brucei brucei have been grown. These crystals diffract to at least 2 Å, even after 60 hours of exposure to X-rays. The space group is P212121, with cell dimensions a = 112.4 A?, b = 97.8 A?, c = 48.0 A?. There is one dimer per asymmetric unit.  相似文献   

11.
Conditions have been established for the crystallization of tyrosyl-transfer RNA synthetase from Bacillus stearothermophilus at room temperature. The crystals are extremely well-ordered, exhibiting diffraction spots out to at least 2.7 Å, and can be grown to a convenient size for X-ray crystallographic analysis. The crystals are trigonal with a space group P3121, the unit cell having dimensions of a = 64.4 A? and c = 238 A?; the crystallographic asymmetric unit is probably one subunit of the dimeric (2 × 45,000, mol. wt) enzyme. The enzyme crystals are extremely stable and exhibit good resistance to radiation damage. This amino-acyl-tRNA synthetase appears to be amenable to complete structure determination by X-ray crystallography.  相似文献   

12.
Erysimum latent virus, a tymovirus, contains 180 protein subunits arranged in a T = 3 icosahedral surface lattice. A cubic crystal form (with space group P213 and a = 414 A?) and a monoclinic form (space group B2, a = 442 A?, b = 422 A?, c = 387 A?, γ = 95 °) have been observed. The asymmetric units of the two crystal forms contain one-third and one whole virus particle, respectively. Two possible packing arrangements of the virus particles in the monoclinic unit cell have been deduced from the low-angle diffraction patterns. X-ray diffraction data from the monoclinic crystals extend to at least 3·7 Å resolution.  相似文献   

13.
Crystals of crambin, a plant seed protein of molecular weight 5000, diffract X-rays strongly to the interplanar spacing limit of 0.88 Å. These diffraction data should allow a definition of atomic structure that is on a par with that typically obtained from crystals of small organic molecules. The crystals are in space group P21 and have unit cell dimensions a = 41.1 A?, b = 18.7 A?, c = 22·7 A?, and β = 90.6 °. The asymmetric unit contains one protein molecule.  相似文献   

14.
Crystals of plastocyanins from pea and corn leaves have been obtained. Both are suitable for X-ray structure analysis with a resolution up to 1.8 Å. The crystal form of plastocyanin from pea leaves belongs to the space group P212121 with unit cell dimensions: a = 49.0 A?, b = 53.3 A?, c = 82.6 A?. The assumed number of protein molecules per asymmetric unit of the unit cell is two. Crystals of the oxidized (Cu2+) and reduced (Cu+) forms are isomorphic. No essential differences in spot intensities for the main zone with a resolution of 3 Å were revealed. The crystal form of plastocyanin from corn leaves belongs to the space group P1 with unit cell parameters: a = 24.8 A?, b = 30.0 A?, c = 58.5 A? and α = 96° 10′, β = 87°08′, γ = 78°40′. The assumed number of protein molecules per asymmetric unit is two.  相似文献   

15.
Large single crystals of isocitrate dehydrogenase from Azotobacter vinelandii have been grown by vapor diffusion from ammonium sulfate and phosphate solutions. The crystals are tetragonal, space group P42212 with cell dimensions a = 122.1 A?, c = 163.9 a?. There are two molecules of 80,000 molecular weight per asymmetric unit. Native data to 5.5 Å resolution have been collected on a diffractometer. A rotation function using data between 10 Å and 6 Å resolution indicates three possible orientations of the non-crystallographic 2-fold axis relating the two molecules.  相似文献   

16.
Poliovirus contains 60 copies each of four coat protein subunits arranged on a T = 1 icosahedral surface. Crystals of the Mahoney and the Sabin strains of the type I serotype of polio have been obtained. Crystals of the Mahoney strain belong to the orthorhombic space group P21212 with a = 324 A?, b = 359 A?, c = 381 A?, contain 12 virus particle in the asymmetric unit, and diffract to at least 2.5 Å resolution. The crystals are apparently identical to those characterized by Finch & Klug (1959). Collection of three-dimensional X-ray diffraction data to 2.9 Å resolution is in progress.  相似文献   

17.
Uteroglobin is a steroid-binding protein of 15,800 molecular weight, composed of two chemically identical subunits which, in the oxidized form, are covalently linked by disulphide bridges. Large crystals have been grown from ammonium sulphate solutions by vapour diffusion as well as by equilibrium dialysis. The crystals are very stable under X-rays, diffract to at least 2.2 Å resolution and belong to space group P21. The unit cell, with dimensions a = 43.3 A?, b = 31.1 A?, c = 34.5 A?, and β = 90.7 °, contains two dimeric molecules. The crystals exhibit a prominent pseudo symmetry corresponding to space group P21212 which indicates that the two subunits should be structurally nearly identical.  相似文献   

18.
Belladonna mottle virus belongs to the turnip yellows mosaic virus group of the small spherical plant viruses. It contains 180 protein subunits, which are arranged in a T = 3 icosahedral surface lattice. The top and bottom viral components crystallize isomorphously in hexagonal space group R3 (a = b = 296 A?, c = 729 A?). The unit cell contains three virus particles, while the crystallographic asymmetric unit consists of only one-third of a particle. X-ray diffraction data from the crystals extend to at least 3.8 Å resolution.  相似文献   

19.
Bovine pancreatic deoxyribonuclease I has been crystallized using the method of precipitation by polyethylene glycol 6000. The crystals diffract to 1.8 Å and belong to space group C2 with cell dimensions: a = 131.6 A?, b = 54.9 A?, c = 38.4 A?, β = 91.4 ° and one molecule per asymmetric unit.  相似文献   

20.
Crystals of human milk α-lactalbumin have been grown from ammonium sulfate solutions in the presence of calcium ions at 35 °C. They belong to space group P21212, with unit cell dimensions: a = 33.6 A?, b = 69.9 A?, c = 47.3 A? and have a single molecule in the asymmetric unit. The crystals diffract X-rays strongly to Bragg spacings of 2 Å and appear suitable for X-ray structural analysis.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号