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  • 1
    ISSN: 1573-3904
    Keywords: antibiotic ; isotope labeling ; peptaibol ; peptidesynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Synthesis of zervamicin IIB, specifically labeled at the α-position of glutamine-11 with 15N, was achieved by the Fmoc/tert.-butyl strategy in solution using a fragment condensation approach. Three fragments of zervamicin IIB were obtained by stepwise elongation with Fmoc amino acids using BOP as a coupling reagent. For the introduction of the highly sterically hindered α-aminoisobutyric acid residues, BOP/DMAP activation was applied. Peptide fragments were coupled by means of the coupling reagent, CF3-PyBOP. Using the strategy developed, zervamicin IIB specifically 15N labeled has been synthesized in 30% overall yield based on the isotopically labeled amino acid. From 600 MHz NMR spectroscopy the position of the 15N-label was clearly detected. The isotope enrichment (98 ± 2%) was determined by FAB-mass spectrometry.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-3904
    Keywords: antibiotic ; isotope labeling ; peptaibol ; peptide synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Synthesis of zervamicin IIB, specifically labeled at the α-position of glutamine-11 with15N, was achieved by the Fmoc/tert.-butyl strategy in solution using a fragment condensation approach. Three fragments of zervamicin IIB were obtained by stepwise elongation with Fmoc amino acids using BOP as a coupling reagent. For the introduction of the highly sterically hindered α-aminoisobutyric acid residues, BOP/DMAP activation was applied. Peptide fragments were coupled by means of the coupling reagent, CF3-PyBOP. Using the strategy developed, zervamicin IIB specifically15N labeled has been synthesized in 30% overall yield based on the isotopically labeled amino acid. From 600 MHz NMR spectroscopy the position of the15N-label was clearly detected. The isotope enrichment (98 ±2%) was determined by FAB-mass spectrometry.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0991
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. A number of bacteria are able to synthesize 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate (BOSS) in response to oxidative stress. Here we show that the ability to synthesize BOSS can be genetically transferred from Corynebacterium ammoniagenes to Escherichia coli. A total DNA library from C. ammoniagenes ATCC 6872 established in the pBluescript SKII+ vector backbone was transfected into E. coli XL-1 blue. Recombinant clone 2–31, which was resistant to redox-cycling agents, was selected. NMR studies showed that this clone was able to synthesize BOSS. We also studied the resistance of clone 2–31 to the bactericidal action of macrophages. Clone 2–31 cells had better survival within murine peritoneal macrophages than parental E. coli XL-1-blue cells. Since the ability to synthesize BOSS correlates with increased survival of bacteria within macrophages, we suggest that the pathogenicity of Corynebacteria could be mediated through the synthesis of BOSS.
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  • 4
    ISSN: 0947-3440
    Keywords: Peptaibol ; Zervamicin ; Synthesis ; Aib ; Fmoc ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The isotopically labelled C-terminal fragment of zervamicin, H-Hyp10-[4,4-2H2-Gln]-Aib-Hyp-Aib-Pro-Phl16, has been synthesized in solution by a Fmoc/tert-butyl strategy in 28% overall yield. The Fmoc group was removed by reaction for 2 min with 0.1 M NaOH in dioxane/methanol/water, (30:9:1, v:v:v). The couplings of the sterically hindered Aib residues were achieved by means of either BOP/DMAP activation or Fmoc-Aib-Cl. Acid deprotection of the peptide was performed by reaction with 50% TFA in CH2Cl2 for 30 min without significant cleavage of the acid-labile Aib-Pro and Aib-Hyp peptide bonds.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Peptide Science 3 (1997), S. 193-208 
    ISSN: 1075-2617
    Keywords: peptaibol ; antibiotic ; peptide synthesis ; NMR spectroscopy ; mass spectrometry ; isotope labelling ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For the first time the total synthesis of the peptaibol antibiotic zervamicin IIB is described. Synthesis of this peptaibol was achieved by the Fmoc/tert-butyl strategy in solution using a fragment condensation approach. Three fragments of zervamicin IIB were obtained by stepwise elongation with Fmoc amino acids using BOP as a coupling reagent. For the introduction of the highly sterically hindered α-aminoisobutyric acid residues BOP/DMAP activation was applied. The Fmoc group was removed by reaction with 0.1 M NaOH in dioxane/methanol/water (30/9/1, v/v/v). Peptide fragments were coupled by means of a new coupling reagent, CF3-PyBOP. Using the strategy developed, zervamicin IIB and two analogues specifically deuterium-labelled at different positions of the glutamine-11 residue have been synthesized in 40% overall yield based on the isotopically labelled amino acid and with 98±2% of isotope enrichment. FAB mass spectroscopy, 600 MHz 1H-NMR spectroscopy and high-performance liquid chromatography provided convincing evidence that the synthetic products, zervamicin IIB and its deuterium-labelled analogues, fully correspond to the naturally occurring zervamicin IIB. © 1997 European Peptide Society and John Wiley & Sons, Ltd.
    Additional Material: 8 Ill.
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  • 6
    ISSN: 1434-193X
    Keywords: α,α-Dialkylated amino acids ; Isotopic labeling ; Strecker synthesis ; Solvent effects ; Stereoselective hydrolysis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---[15N]-D-isovaline was prepared from DL-[α-15N]-α-aminoisovaleramide by enzymatic resolution with Mycobacterium neoaurum. The 15N-isotope was introduced during the Strecker synthesis of its precursor, e.g. aminoisovaleronitrile. Attempts to prepare the amino nitrile precursor of [15N]-α-aminoisobutyric acid (Aib) led to a poor yield and loss of the label. Significantly, improved results were obtained when a cosolvent is present during formation of aminoisobutyronitrile.
    Additional Material: 1 Ill.
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  • 7
    ISSN: 1432-072X
    Keywords: Key words 2-C-methyl-d-erythritol ; Xanthomonas ; Pseudomonas ; Corynebacterium ; Isoprenoid ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this study, the gram-negative bacteria Xanthomonas campestris, Xanthomonas maltophilia, and Pseudomonas putida, facultative parasites of plants and animals, were shown to accumulate 2-C-methyl-d-erythritol-2,4-cyclopyrophosphate (MEC) in response to benzyl-viologen-induced oxidative stress. Corynebacterium ammoniagenes mutants capable of accumulating MEC in the absence of an exogenous oxidative stress inducer were obtained. Isoprenoid synthesis and MEC synthesis in these and other bacteria were shown to be alternative processes, while biosynthesis of brominated polyene xanthomonadin (an antioxidant pigment of X. campestris) increased concomitantly with the accumulation of MEC.
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