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Ugo Orcel Dr. Matteo De Poli Dr. Marta De Zotti Prof. Jonathan Clayden 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(48):16357-16365
The N‐terminal nonapeptide domain of the fungal nonribosomal peptide antibiotics cephaibol A and cephaibol C (AcPheAib4LeuIvaGly‐ Aib) is reported to adopt a right‐handed helical conformation in the crystalline state. However, this conformation is at odds with the left‐handed helicity observed in solution in related synthetic oligomers capped with Ac‐L ‐PheAib4 fragments. We report the synthesis of four diastereoisomers of the cephaibol N‐terminal nonapeptide, and show by NMR and CD spectroscopy that the peptide containing the chiral amino acids Phe and Leu in the naturally occurring relative configuration exists in solution as an interconverting mixture of helical screw‐sense conformers. In contrast, the nonapeptide containing the unnatural relative configuration at Phe and Leu adopts a single, stable helical screw‐sense, which is left handed when the N‐terminal Phe residue is L and right‐handed when the N‐terminal Phe residue is D . 相似文献
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Dr. Sven Weigelt Dr. Thomas Huber Frank Hofmann Dr. Micha Jost Markus Ritzefeld Prof. Dr. Burkhard Luy Dr. Christoph Freudenberger Prof. Dr. Zsuzsanna Majer Prof. Dr. Elemér Vass Dr. Jörg‐Christian Greie Dr. Lavinia Panella Dr. Bernard Kaptein Dr. Quirinus B. Broxterman Prof. Dr. Horst Kessler Prof. Dr. Karlheinz Altendorf Prof. Dr. Miklós Hollósi Prof. Dr. Norbert Sewald 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(10):3264-3264
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Weigelt S Huber T Hofmann F Jost M Ritzefeld M Luy B Freudenberger C Majer Z Vass E Greie JC Panella L Kaptein B Broxterman QB Kessler H Altendorf K Hollósi M Sewald N 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(2):478-487
The efrapeptin family of peptide antibiotics produced by the fungus Tolypocladium niveum, and the neo‐efrapeptins from the fungus Geotrichum candidumare inhibitors of F1‐ATPase with promising antitumor, antimalaria, and insecticidal activity. They are rich in Cα‐dialkyl amino acids (Aib, Iva, Acc) and contain one β‐alanine and several pipecolic acid residues. The C‐terminus bears an unusual heterocyclic cationic cap. The efrapeptins C–G and three analogues of efrapeptin C were synthesized using α‐azido carboxylic acids as masked amino acid derivatives. All compounds display inhibitory activity toward F1‐ATPase. The conformation in solution of the peptides was investigated with electronic CD spectroscopy, FT‐IR spectroscopy, and VCD spectroscopy. All efrapeptins and most efrapeptin analogues were shown to adopt helical conformations in solution. In the case of efrapeptin C, VCD spectra proved that a 310‐helix prevails. In addition, efrapeptin C was conformationally studied in detail with NMR and molecular modeling. Besides NOE distance restraints, residual dipolar couplings (RDC) observed upon partial alignment with stretched PDMS gels were used for the conformational analysis and confirmed the 310‐helical conformation. 相似文献
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