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1.
A complete human κ-type Bence—Jones protein (Fin) has been isolated and crystallized. Immunochemical and physicochemical characterization of protein Fin indicates that it is of the κ-chain subgroup, κII, and that it consists of two non-covalently bound intact monomers having a molecular weight of ~23,000 Crystals of Bence—Jones protein Fin obtained from ammonium sulfate solutions have the orthorhombic space group P212121 with cell dimensions a = 132.0 A?, b = 93.3 A?, and c = 42.3 A?. The asymmetric unit consists of a dimer of molecular weight ~46,000.  相似文献   

2.
A “naturally occurring” human κI VL dimer, designated Wat, has been isolated and crystallized. Protein Wat consists of two non-covalently bound monomers, each having a molecular weight of ~ 11,500. The monomer subunit is composed of an entire variable region light chain (VL) domain closely homologous to that of the κI Bence Jones protein Roy (Hilschmann &; Craig, 1965) as evidenced from amino acid composition, tryptic peptide map, and sequence analysis. Immunochemical studies substantiated that protein Wat is of the κ chain subgroup κI and lacks the isotypic and allotypic antigenic determinants associated with the κ constant region light chain domain. Two types of crystals of VL dimer Wat were obtained from ammonium sulfate or polyethylene glycol solutions. The type I crystals have unit cell dimensions of a = b = 82.6 A?, c = 60.3 A?, and the space group is hexagonal P62 or P64. The asymmetric unit consists of one VL dimer; the fractional volume of unit cell occupied by solvent is 0.51. The unit cell dimensions of the type II crystals are a = b = 1,08.3 A?, c = 108.8 A?; the space group is hexagonal P6122 or P6522. Three variable domains constitute the asymmetric unit of the type II crystals; the fractional value of the solvent (0.52) is compatible with the value obtained for the type I crystals.  相似文献   

3.
Superoxide dismutase from Bacillus stearothermophilus is a dimeric manganese-containing enzyme with a molecular weight of 40,000. It has been crystallised in the monoclinic space group P21 with unit cell dimensions of a = 50 A?, b = 70 A?, c = 69 A? and β = 111 ° 10′. The asymmetric unit appears to be the dimer.  相似文献   

4.
Lactoglobulin isolated from Italian buffalo milk has been crystallized in two different forms. Crystals of type I have been grown at pH 3.5 and belong to space group P63; the unit cell dimensions are a = b = 67 A?, c = 142 A?, and accordingly the asymmetric unit contains one dimer of molecular weight 36,000. Type II crystals, grown at pH 8.5, have only one monomer per asymmetric unit; the space group is P3121 (or enantiomorph) and the unit cell edges are: a = b = 54.4 A?, c = 113.2 A?. The crystals of the trigonal form show low radiation damage and are suitable for a structural investigation.  相似文献   

5.
Cytochrome c7, a low potential, three heme-containing protein (molecular weight 9800) was isolated from Desulfuromonas acetoxidans and crystallized from polyethylene glycol solutions. The crystals belong to the orthorhombic space group P212121, with unit-cell dimensions a = 44·10 A?, b = 37·55 A? and c = 45·08 A? and have one molecule of protein per asymmetric unit.  相似文献   

6.
The TET-repressor encoded by the transposon Tn10 has been crystallized along with the repressor-tetracycline complex. Both crystals belong to the space group P43212 (or P41212) with cell dimensions a = b = 74.3(1) A?, c = 94.2(2) A? and a = b = 73.3(1) A?, c = 94.6(2) A? for the free and complexed repressor, respectively. There is one molecule of molecular weight 23,000 per asymmetric unit, and the biologically active dimer therefore consists of two identically formed subunits which are related by a crystallographic 2-fold axis. This isomorphism of TET-repressor and its tetracycline complex suggests that only minor, subtle changes in structure trigger binding to or release of the operator. The crystals of the native protein permit X-ray data collection to 3.2 Å and those of the complexed repressor to 2.8 Å.  相似文献   

7.
Crystals of the periplasmic ribose binding protein of Salmonella typhimurium have been subjected to X-ray analysis. The crystals grow as rectangular parallelopipeds with the symmetry of space group P21. Unit cell dimensions are a = 64·4 A?, b = 60·6 A?, c = 62·8 A?, and β = 91·25 °. There are two molecules of molecular weight 29,000 per asymmetric unit.  相似文献   

8.
EcoRI endonuclease crystallizes in space group C2 with unit cell parameters a = 209 A?, b = 129 A?, c = 50 A? and β = 98.4 °. Four 29,000 molecular weight subunits per asymmetric unit would give a reasonable Vm value of 2.87 Å3/dalton. EcoRI endonuclease is the first protein which recognizes a specific sequence of bases in DNA to be crystallized in a form suitable for high resolution structure analysis.  相似文献   

9.
Crystals of histidinol dehydrogenase (EC 1.1.1.23) from Salmonella typhimurium have been obtained in large size suitable for single crystal X-ray studies. The following crystal data were obtained on examination of a number of X-ray precession photographs; crystal system monoclinic, a = 149.6 A?, b = 88.9 A?, c = 105.6 A?, β = 124.5 °, space group C2. The density of the crystal measured by flotation in bromobenzene/xylene mixture is 1.186 g/cm3. There is one dimer molecule of molecular weight 80,000 in one crystallographically asymmetric unit.  相似文献   

10.
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   

11.
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   

12.
Two closely related crystal forms of dimeric cytochrome c5 from Azotobacter rinelandii have been grown. The crystals belong to space groups (C2 with a = 45·0, b = 38·4, c = 41·3 A? and β = 101 ° 0′; and C1 (a centered triclinic cell) with a = 46·0, b = 37·6, c = 49·4 A?, α = 87 ° 20′, β = 96 ° 40′ and γ = 90 ° 0′. In C2 the 24,000 molecular weight dimer lies on a Crystallographic 2-fold axis; in C1 the entire dimer occupies the asymmetric unit.  相似文献   

13.
The Fc fragment was prepared from rabbit immunoglobulin G by digestion with papain, both with the inter-chain disulphide bond intact, and after reduction and alkylation. These two types of Fc crystallized in different, yet related forms, each with one dimer in the asymmetric unit. The covalently linked dimer crystallized in space group P21; a = 68.85 ± 0.05 A?, b = 72.50 ± 0.05 A?, c = 60.40 ± 0.05 A? and β = 105.1 ± 0.2 °. The reduced, non-covalently linked dimer also crystallized in space group P21; a = 81.55 ± 0.05 A?, b = 55.65 ± 0.05 A?, c = 68.85 ± 0.05 A? and β = 1051 ± 0.2 °. A non-crystallographic 2-fold axis relating the two identical polypeptide chains is clearly visible in the h0l projection of the second crystal form.  相似文献   

14.
Three crystal forms of rabbit muscle creatine kinase have been grown, one of which seems suited to a high resolution X-ray diffraction study. The first form is of monoclinic space group P21 with a = 54 A?, b = 114 A?, c = 145 A?, β = 91 ° and has as the asymmetric unit two molecules of total molecular weight 160, 000. The second form, grown in the presence of mercurials, is of space group A2 with a = 52 A?, b = 165 A?, c = 237 A?, β = 91 ° and also has two molecules in the asymmetric unit. The third crystal form, grown in the presence of a high concentration of cysteine, is of apparent space group P212121, but evidence indicates that the true space group may be P21221. The dimensions of the orthorhombic unit cell are a = 47 A?, b = 86 A?, c = 125 A?, and the asymmetric unit contains a single protein subunit. Assuming the latter space group, then the creatine kinase molecule possesses a twofold axis relating two identical subunits.  相似文献   

15.
Crystals of lysozyme from Streptomyces erythraeus are orthorhombic, space group P212121 with unit cell dimensions: a = 50.01 A?, b = 61.98 A? and c = 67.85 A?; and one molecule, of molecular weight about 18,500, per asymmetric unit.  相似文献   

16.
Crystals of the bacteriophage λ Cro repressor protein that are suitable for X-ray diffraction studies have been obtained. Preliminary crystallographic analysis reveals that the space group is R32, the cell dimensions in the hexagonal system are a = b = 91·9 A?, c = 268·9 A?, and there are three dimers per asymmetric unit.  相似文献   

17.
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   

18.
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   

19.
The serotype B of exfoliative toxin, isolated from Staphylococcus aureus, strain TC 142, has been crystallized. The monoclinic crystals belong to space group P21, with a = 55.9 A?, b = 107.9 A?, c = 42.8 A?, and β = 90.9 °. The asymmetric unit contains two molecules of molecular weight 30,000.  相似文献   

20.
Superoxide dismutase from spinach leaves was salted out with ammonium sulphate. The resulting crystals were monoclinic, space group C2, with unit cell dimensions a = 166.2 A?, b = 46.1 A?, c = 85.6 A? and β = 99.3 °. Considerations of cell volume and protein molecular weight indicated two molecules of superoxide dismutase in the asymmetric unit.  相似文献   

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