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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 70-85 
    ISSN: 0887-3585
    Keywords: Protein electrostatics ; protein kinases ; effector protein ; calciumbinding protein ; α-helix ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Calmodulin's calculated electrostatic potential surface is asymmetrically distributed about the molecule. Concentrations of uncompensated negative charge are localized near certain α-helices and calcium-binding loops. Further calculations suggest that these charge features of calmodulin can be selectively perturbed by changing clusters of phylogenetically conserved acidic amino acids in helices to lysines. When these cluster charge reversals are actually produced by using cassette-based site-specific mutagenesis of residues 82-84 or 118-120, the resulting proteins differ in their interaction with two distinct calmodulin-dependent protein kinases, myosin light chain kinase and calmodulin-ldependent protein kinase II. Each calmodulin mutant can be purified to apparent chemical homogeneity by an identical purification protocol that is based on conservation of its overall properties, including calcium binding. Although cluster charge reversals result in localized perturbations of the computed negative surface, single amino acid changes would not be expected to alter significantly the distribution of the negative surface because of the relatively high density of uncompensated negative charges in the region around residues 82-84 and 118-120. However, this does not preclude the possibility of single amino acid charge perturbations having a functional effect on the more intimate, catalytically active complex. The electrostatic surface of calmodulin described in this report may be a feature that would be altered only by cluster charge reversal mutations. Overall, the results suggest that the charge properties that are important for the efficient assembly of calmodulin-protein kinase signal transduction complexes in eukaryotic cells.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complete sequential assignment of the 1H-nmr resonance frequencies of the active fragment of the rat atrial natriuretic factor (ANF 101-126) has been performed. Two-dimensional nmr techniques have been employed, including phase-sensitive nuclear Overhauser spectroscopy (NOESY), relayed coherence transfer spectroscopy (RELAY), and J-correlated spectroscopy (COSY). Experiments were performed both in D20 and H20 solutions at different pH values. With few exceptions, resonance frequencies were practically pH independent. NOESY spectra were recorded using both 300- and 500-ms mixing times, and no long-range connectivities were observed, leading to the conclusion that ANF 101-126 has no defined secondary nor tertiary structure in water in the pH range used (2.73-5.21).
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 18 (1994), S. 107-118 
    ISSN: 0887-3585
    Keywords: protein crystallography ; four helix bundle ; iron ; macromolecular assembly ; regulation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Ferritin is a 24 subunit protein that controls biomineralization of iron in animals, bacteria, and plants. Rates of mineralization vary among members of the ferritin family, particularly between L and H type subunits of animal ferritins which are differentially expressed in various cell types. To examine ferritin from a highly differentiated cell type and to clarify the relationship between ferritin structure and function, bullfrog red cell L ferritin has been cloned, overexpressed in E. coli, and crystallized under two conditions. Crystals were obtained at high ionic strength in the presence of MnCl2 at a concentration comparable to that of the protein and in the presence of MgCl2 at a concentration much higher than that of the protein. Under both crystallization conditions, the crystals are tetragonal bipyramids in the space group F432 with unit cell dimensions a=b=c= 182 ± 0.5 Å. Crystals obtained in the presence of manganese and ammonium sulfate diffract to 1.9 Å, while those obtained in the presence of magnesium and sodium tartrate diffract to 1.6 Å. Isomorphous crystals have been obtained under similar conditions for a site-directed mutant with a reduced mineralization rate in which Glu-57, -58, -59, and -61 are all replaced by Ala. The structure of wild type L-subunit with magnesium has been solved by molecular replacement using the calcium salt of human liver H subunit (Lawson et al., Nature (London) 349:541-544, 1991) as the model. The crystallographic R factor for the 6-2.2 Å shell is 0.21. The overall fold of human H and bullfrog L ferritins is similar with an rms difference in backbone atomic positions of 0.97 Å. The largest structural differences occur in the D helix and the loop connecting the D and E helices of the four helix bundle. Because red cell L ferritin and liver H ferritin show differences in both rates of mineralization and three-dimensional structure, more detailed comparisons of these structures are likely to shed new light on the relationship between conformation and function. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 51 (1968), S. 206-210 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A total synthesis of hystrine has been realised with good yield by the introduction of a double link into the piperidine nucleus of synthetic ammodendrine, followed by deacetylation, and purification with the aid of the nitroso derivative.The identity of the synthetic product with authentic hystrine was established by its chromatographic behaviour, by UV.-, IR.- and mass spectra as well as by the properties of its nitroso derivative. Thus the proposed structure of hystrine as 3-(2, 3, 4, 5-tetrahydropyrid-6-yl)-1, 4, 5, 6-tetrahydropyridine (V) is proved.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 442 (1978), S. 225-229 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Fluorescence Properties of Copper (I) CarboxylatesBy reduction of copper(II) carboxylates with ascorbic acid in aqueous solutions some aromatic copper(I) compounds can easily be obtained by precipitation. Powder x-ray photographs of copper(I) propionate and copper(I) monochloroacetate have similar characteristic interferences as copper(I) acetate, from which a layer structure is known. All the here described copper(I) carboxylates are fluorescent, indicating that oxygen atoms behave as sufficently strong donors, but most of them and especially those with tetragonal structure, do not change their fluorescence colour by cooling in liquid nitrogen like many copper(I) complexes with nitrogen bases do (fluorescence thermochromism). Fluorescence thermochromism occurs however at copper(I) 3-hydroxybenzoate. This presumably results from a lower symmetry.
    Notes: Einige aromatische Kupfer(I)-Verbindungen lassen sich auf einfache Weise in wäßriger Lösung durch Reduktion mit Ascorbinsäure darstellen. Die Debyeogramme von Kupfer(I)-Propionat und Kupfer(I)-monchloracetat haben die ähnlichen charakteristischen Interferenzringe wie Kupfer(I)-acetat, welches Schichtenstruktur besitzt. Da alle hier beschriebenen Kupfer(I)-carboxylate fluoreszieren, zeigt es sich, daß die Sauerstoffatome ausreichend starke Donoreigenschaften haben. Die meisten und speziell die, welche tetragonale Struktur besitzen, ändern ihre Fluoreszenzfarbe nicht im Gegensatz zu vielen Kupfer(I)-Amin-Komplexen (Fluoreszenzthermochromie). Kupfer(I)-3-hydroxybenzoat zeigt jedoch Fluoreszenzthermochromie, was wahrscheinlich auf eine geringere Symmetrie Zurückzuführen ist.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 13 (1995), S. 211-216 
    ISSN: 0263-6484
    Keywords: n-3 polyunsaturated fatty acids ; CD36 ; monocytic cells ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: CD36, a multifunctional adhesion receptor e.g. for thrombospondin and collagen, as well as a scavenger receptor for oxidized low density lipoprotein, is expressed e.g. on platelets and monocytes. By this dual role it might be involved in early steps of atherosclerosis like the recruitment of monocytes and formation of foam cells. We therefore studied the effects of n-3 fatty acids on CD36 expression in human monocytic cells. Incorporation of eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3) into cellular phospholipids resulted in a significant reduction of CD36 expression at the mRNA and protein level, whereas arachidonic acid (AA, C20: 4n-6) and linoleic acid (LA, C18:2n-6) tended to increase CD36 expression compared to the control. This specific down-regulation of CD36 by n-3 fatty acids in cells involved in the initiation and progression of atherogenesis and inflammation, represents a further mechanism that may contribute to the beneficial effects of n-3 polyunsaturated fatty acids (PUFA) in these disorders.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 13 (1995), S. 273-277 
    ISSN: 0263-6484
    Keywords: adhesion ; HMG-CoA reductase ; HUVEC ; mevalonate ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The proliferation of human monocytic Mono Mac 6 cells was significantly retarded by treatment with lovastatin (LOV, 10 μM) for 72 h. Treatment of Mono Mac 6 cells with LOV increased surface protein expression of monocyte-associated CD14 and the integrin-chain CD11b towards levels found in isolated human blood monocytes. These effects were dose-dependent and completely reversed by the isoprenoid precursor mevalonate (MVA). LOV failed to induce growth retardation and upregulation of CD11b or CD14 in the less mature premonocytic U937 cell line. While CD11b expression was comparable in Mono Mac 6 cells treated with LOV (10 μM), TNF (100 U ml-1) or LPS (10 ng ml-1), upregulation of CD14 by LOV was less pronounced. Basal CD23 expression was unaffected by LOV but markedly reduced by treatment with TNF or LPS. Moreover, LOV enhanced Mono Mac 6 adhesiveness to human umbilical vein endothelial cells to levels found in isolated human blood monocytes, probably due to the increased CD11b and CD14 expression. In conclusion, LOV can induce differentiation of monocytic cells which is reflected by the retardation of growth, expression of CD14 and CD11b, and enhanced adhesiveness.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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