Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Methylmalonyl-CoA epimerase (MMCE) is an enzyme that interconverts the R and S epimers of methylmalonyl-CoA in the pathway that links propionyl-CoA with succinyl-CoA. This is used for both biosynthetic and degradative processes, including the breakdown of odd-numbered fatty acids and some amino acids. The enzyme has been expressed in Escherichia coli both as the native enzyme and as its selenomethionine (SeMet) derivative. Crystals of both forms have been obtained by vapour diffusion using monomethylether PEG 2000 as precipitant. The native MMCE crystals are orthorhombic, with unit-cell parameters a = 56.0, b = 114.0, c = 156.0 Å, and the SeMet-MMCE crystals are monoclinic, with unit-cell parameters a = 43.6, b = 78.6, c = 89.4 Å, β = 92.0°; both diffract to better than 2.8 Å resolution.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Human bile-salt dependent lipase (BSDL), secreted into both the digestive tract and human milk, is integral to the effective absorption of dietary lipids. In attempts to obtain crystals suitable for high-resolution X-ray crystallographic studies, various forms of the enzyme have been crystallized, including native and desialidated human milk BSDL and both intact recombinant BSDL and a truncated form lacking the heavily glycosylated C-terminal repeat region. Trigonal crystals of native BSDL, with unit-cell parameters a = b = 90.0, c = 156.1 Å, were obtained using 15–20%(w/v) PEG 8000 as precipitant. These crystals diffract to 3.5 Å along the unique axis, but to only 5–7 Å in orthogonal directions. Crystals of recombinant truncated BSDL grown from 15–20%(w/v) PEG 6000 are orthorhombic, space group P212121, with unit-cell parameters a = 59.2, b = 90.0, c = 107.7 Å, and diffract to 2.6 Å resolution. These are suitable for structural analysis by X-ray crystallography.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: A variety of human haemoglobins (Hbs) are produced at different stages of human development, including three embryonic Hbs, foetal Hb and adult Hb. All are heterotetramers. During crystallization experiments on human embryonic Hb Portland (ζ2γ2), it was discovered by crystallographic and biochemical analysis that the homotetramer Hb Bart's (γ4) preferentially crystallizes from ζ2γ2 solutions below pH 5. This results from dissociation of Hb Portland into γ2 dimers and ζ monomers and has interesting implications for subunit interactions and tetramer stability in Hbs. It also makes possible a full crystallographic analysis of Hb Bart's, which is of considerable medical significance because of its presence in the red blood cells of millions of people worldwide who suffer from α-thalassaemia.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 50 (1994), S. 302-316 
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The three-dimensional structure of human dicupric monooxalate lactoferrin, Cu2oxLf, has been determined to 2.0 Å resolution, using X-ray diffraction data collected by diffractometry to 2.5 Å resolution, and oscillation photography on a synchrotron source to 2.0 Å resolution. Difference electron-density maps calculated between Cu2oxLf and both dicupric lactoferrin, Cu2Lf, and diferric lactoferrin, Fe2Lf, showed that the oxalate had replaced a carbonate in the C-terminal binding site, and that, relative to Cu2Lf, there were no significant differences in the N-terminal site. The structure was then refined crystallographically by restrained least-squares methods. The final model, in which the r.m.s. deviation in bond distances is 0.017 Å, contains 5314 protein atoms (691 residues), two Cu2+ ions, one bicarbonate ion, one oxalate ion, 325 solvent molecules and one sugar residue. The crystallographic R factor of 0.193 is for 46 134 reflections in the range 8.0 to 2.0 Å resolution. The oxalate ion is coordinated to copper in a 1,2-bidentate fashion, and the added bulk of the anion results in the rearrangement of the side chains of nearby arginine and tyrosine residues. No other major alterations in the molecule can be observed, the overall protein structure being the same as that for Cu2Lf and Fe2Lf.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 50 (1994), S. 429-440 
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: In protein crystallography, the initial experimental problem is the identification of physical and chemical conditions that will support nucleation and crystal growth. Ideally, experiments to search for such conditions would be based on a full-factorial structure, with variation in the temperature and solution composition. However, consideration of even a moderate number of possibilities for the composition of the system will result in factorial experiments which may be prohibitively large. In this paper it is proposed that search experiments for protein crystallization might be based on orthogonal arrays. These are subsets of full-factorial experiments which possess a great deal of symmetry, such that a uniform distribution of points throughout the experimental region is preserved. Such experiments have reasonable size, explore the proposed experimental region in a systematic fashion, and form a logical basis for a sequential approach to the search for crystallization conditions. Examples of such initial search experiments are given, and their application to some recent protein crystallization problems in this laboratory is described briefly. The relationship of this approach to other protein crystallization search procedures is also discussed.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The iron-dependent alcohol dehydrogenase from Zymomonas mobilis has been crystallized in a form suitable for X-ray diffraction studies. The crystals grew in hanging drops by vapor diffusion, equilibrating with a solution comprising 25–27% methoxypolyethylene glycol 5000 and 1 mM Co2+ in a 0.2 M succinic acid/potassium hydroxide buffer at pH 5.5–5.7 at 281 K. Crystals are tetragonal, P4122 (or P4322), with unit-cell dimensions a = b = 125.7, c = 248.1 Å. Four molecules comprise the asymmetric unit, and a self-rotation function indicates twofold local symmetry perpendicular to the unique axis and 15° from a crystallographic twofold axis. Diffraction data to 3.0 Å have been collected.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 55 (1999), S. 403-407 
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Human lactoferrin (hLf) has considerable potential as a therapeutic agent. Overexpression of hLf in the fungus Aspergillus awamori has resulted in the availability of very large quantities of this protein. Here, the three-dimensional structure of the recombinant hLf has been determined by X-ray crystallography at a resolution of 2.2 Å. The final model, comprising 5339 protein atoms (residues 1–691, 294 solvent molecules, two Fe3+and two CO_3^{2-} ions), gives an R factor of 0.181 (free R = 0.274) after refinement against 32231 reflections in the resolution range 10–2.2 Å. Superposition of the recombinant hLf structure onto the native milk hLf structure shows a very high level of correspondence; the main-chain atoms for the entire polypeptide can be superimposed with an r.m.s. deviation of only 0.3 Å and there are no significant differences in side-chain conformations or in the iron-binding sites. Dynamic properties, as measured by B-value distributions or iron-release kinetics, also agree closely. This shows that the structure of the protein is not affected by the mode of expression, the use of strain-improvement procedures or the changes in glycosylation due to the fungal system.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 50 (1994), S. 380-384 
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Enzymatic deglycosylation has been used in attempts to crystallize several glycoproteins with the aim of overcoming the problems resulting from heterogeneity and flexibility of the attached glycan chains. An endoglycosidase preparation from Flavobacterium meningosepticum, comprising the enzymes endo F and PNGase-F, was used in experiments on the mammalian binding proteins lactoferrin and haemopexin. Significant differences were found in the susceptibility of different proteins to deglycosylation. For human lactoferrin (Lf) and its recombinant N-terminal half-molecule (LfN), deglycosylation was rapid and complete, and was essential for obtaining high-quality crystals of both apo-Lf and LfN; for bovine Lf, however, complete deglycosylation did not occur. Similarly, for rabbit haemopexin the carbohydrate chain on the C-terminal domain was easily removed, but the three chains on the N-terminal domain proved more resistant and their removal led to some fragmentation of the protein. Nevertheless, this approach provided the only means of crystallizing the C-terminal domain and is likely to be useful for other glycoproteins.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 33 (1977), S. 2325-2326 
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 35 (1979), S. 495-497 
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...