Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 2005-2009
  • 1980-1984  (5)
  • 1975-1979  (1)
  • Chemistry  (3)
  • Chiral stationary phases  (1)
  • Emerimicin  (1)
  • Isovaline  (1)
Source
Material
Years
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Resolution of sulphur-containing amino acids by chiral phase gas chromatography (1984)
    Springer
    Chromatographia 18 (1984), S. 287-293 
    Details
    ISSN: 1612-1112
    Keywords: Glass capillary GC-MS ; Chiral stationary phases ; Thio-amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Methyl esters of the pentafluoropropionyl-amino acid derivatives of the tetrafunctional, sulphur-bridged, stereoisomeric lanthionines, cystathionines and β-methyl-lanthionines were resolved on glass capillaries coated with the chiral stationary phase N-propionyl-L-valine-N-tert-butylamide-polysiloxane (Chirasil-Val) within 35min. Interestingly, L-cystathionine elutes before its D-enantiomer in contrast to the usual order of emergence on an L-phase. The method was applied to the polypeptide antibiotic nisin, which contains mesolanthionine and 2S,3S,6R-3-methyl-lanthionine. N-Pentafluoropropionyl-S-alkylthiocysteine methyl esters (R=methyl, ethyl, n- and iso-propyl, n- and sec-butyl, n-octyl, neo-pentyl, cyclohexyl-, benzyl-, tolyl-) were separated on Chirasil-Val within 30min. The identity of all derivatives was shown by combined gas chromatography-mass spectrometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02259079
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Circular dichroism and conformational analysis of the membrane-modifying peptide -N-t-Boc-(Aib-L-Ala)5-Gly-Ala-Aib-Pro-Ala-Aib-Aib-Glu-(OBzl)-Gln-OMe with respect to alamethicin (1980)
    New York : Wiley-Blackwell
    Biopolymers 19 (1980), S. 203-214 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational analysis of the CD spectrum is reported for the synthetic and membrane-modifying nonadecapeptide analog of alamethicin N-t-Boc-(Aib-L-Ala)5-Gly-Ala-Aib-Pro-Ala-Aib-Aib-Glu(OBzl)- Gln-OMe. The CD data are evaluated according to three different methods and are discussed with respect to those obtained from natural alamethicin and suitable models such as N-t-Boc-(Aib-L-Ala)7-OPOE, fragments of the synthetic nonadecapeptide, and the hexadecapeptide N-t-Boc-(Aib-L-Ala)5-Pro-Ala-Aib-Aib-Glu(OBzl)-Gln-OMe. The synthetic nonadecapeptide with the longer helical region exhibits membrane activities comparable to those of alamethicin, whereas the hexadecapeptide with the shorter helix is inactive.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1980.360190114
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and conformation of a polyoxyethylene-bound undecapeptide of the alamethicin helix and (2-methylalanyl-L-alanine)1-7Dedicated to Professor Dr. Theodor Wieland on the occasion of his 65th birthday. (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 425-450 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The stepwise synthesis and conformational studies of the N-terminal helical partial sequence of the membrane-modifying polypeptide antibiotic alamethicin are described. The polyoxyethylen esters of the fragments N-t-Boc-L-Pro-Aib-Ala-Gln-Aib-Val-Aib-Gly-OH and N-Ac-Aib-L-Pro-Aib-Ala-Aib-Ala-Gln-Aib-Val-Aib-Gly-OH are synthesized using polyoxyethylene (molecular mass 10,000) as solubilizing support. CD spectra of each intermediate in ethanol show α-helix formation of the N-protected peptide polymers beginning with the nonapeptide and of the N-protonated sequences beginning with the decapeptide. Compared to the helix of alamethicin, temperature- and solvent-dependent CD measurements indicate analogous conformational behavior. The results suggest that in lipophilic media the alamethicin helix can extend the full length of the partial sequence between the two proline residues and that aqueous media favor an increase of random-coil conformation.For model studies of the particular lipid interaction of alamethicin, the stepwise synthesis of peptides with the alternating (Aib-L-Ala)n sequence (n = 1-7) was carried out on a polyoxyethylene support (molecular mass 6000). CD and ORD studies in ethanol showed a change from the random coil to a right-handed α-helix with increasing peptide length. This change is observed for the N-protected peptides at a chain length of 8 residues and for the N-protonated peptides at a length of 9 residues. The comparison of the CD data of free and polyoxyethylene-bound peptides revealed that the solubilizing polymeric support cannot induce conformational changes. The intensities of the CD bands of t-Boc-(Aib-L-Ala)n-OPOE (n ≥ 6) are higher than those of alamethicin, and these model peptides show similar temperature and solvent inducible changes of their helix contents.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360180217
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Stabilizing effects of 2-methylalanine residues on β-turns and α-helices (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 241-246 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C-, 1H-nmr, CD, and x-ray crystallography revealed β-turns of type III for Boc-Gly-L-Ala-Aib-OMe, Boc-L-Ala-Aib-L-Ala-OMe; the 310-helix for Boc-Aib-L-Ala-Aib-L-Ala-Aib-OMe; and antiparallel arranged α-helices for Boc-L-Ala-Aib-Ala-Aib-Ala-Glu(OBzl)-Ala-Aib-Ala-Aib-Ala-OMe. An N-terminal rigid α-helical segment is found in the polypeptide antibiotics alamethicin, suzukacillin, and trichotoxin. The α-helix dipole is essential for their voltage-dependent pore formation in lipid bilayer membranes, which is explained by a flip-flop gating mechanism based on dipole-dipole interactions of parallel and antiparallel arranged α-helices within oligomeric structures.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220133
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Chromatographic and mass spectrometric characterization of the structures of the polypeptide antibiotics samarosporin and stilbellin and identity with emerimicin (1983)
    Springer
    Chromatographia 17 (1983), S. 679-685 
    Details
    ISSN: 1612-1112
    Keywords: Samarosporin ; Stilbellin ; Emerimicin ; Peptide Antibiotics (peptaibols) ; Fast atom bombardment MS ; Column liquid chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The structural identity of the polypeptide antibiotics, samarosporin I(II) and stilbellin I(II) with emerimicin IV(III) has been established by thin-layer chromatography, quantitative amino acid analysis by ion-exchange chromatography, gas-liquid chromatography of the N-pentafluoropropionyl amino acid n-propyl esters and N,O-bis-pentafluoropropionyl phenylalaninol with quartz capillaries coated with the chiral stationary phase N-propionyl-L-valine-tert-butylamide, and determination of the relative molecular masses and sequence-specific fragments by field desorption fast atom bombardment mass spectrometry. The separation of closely related sequence analogues of the above polypeptides could be achieved by reversed-phase high-performance liquid chromatography with spherical, fully porous octadecylsilyl bonded phases, and 86% aqueous methanol as eluent. The application of both chromatographic and mass spectrometric methods is demonstrated to be most valuable for the characterization of antibiotics with the unusual constituents α-aminoisobutyric acid, isovaline and phenylalaninol. The methology employed is regarded to be applicable to all polypeptide antibiotics of the peptaibol class.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02259320
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Gas chromatographic determination of the configuration of isovaline in antiamoebin, samarosporin (emerimicin IV), stilbellin, suzukacillins and trichotoxins (1980)
    Springer
    Chromatographia 13 (1980), S. 209-214 
    Details
    ISSN: 1612-1112
    Keywords: Configuration ; Chiral phases ; Gas chromatography ; Isovaline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The D-(resp. R) configuration of isovaline (=2-ethylalanine) was proved for the peptide antibiotics antiamoebin, Tü 165 (CBS 382.62), stilbellin, samarosporin (=emerimicin IV), suzukacillin B (A), trichotoxin A-40 and A-50. This contradicts the previously reported L-configuration for isovaline in antiamoebin and emerimicin IV. The configuration was determined by GC of the N-trifluoroacetyl-isovaline n-propyl ester on glass capillary columns coated with the chiral stationary phase N-propionyl-L-valine tert.-butylamide polysiloxane (Chirasil Val). The D-configuration of the isovaline from trichotoxin A-40 was also established independently using GC of N-pentafluoro-propionyl-isovaline (+)-3-methyl-2-butyl esters on glass capillary columns coated with OV 17.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02261873
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...