- Synthesis of [Hexafluorovalyl1,1′]gramicidin S
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[Hexafluorovalyl1,1′]gramicidin S (8), in which two valine residues in the natural gramicidin S were replaced by L-hexafluorovaline (Hfv) residues, was synthesized by the solid-phase-synthesis and cyclization-cleavage method on benzophenone oxime resin. Though the racemic hexafluorovaline derivative was employed for the peptide synthesis, the desired product was isolated in moderate yield, probably reflecting the stable cyclic structure of 8. CD and 1HNMR spectra indicated that the conformation of 8 is similar to that of gramicidin S. The two β-turn structure and antiparallel β-sheet structure with four intramolecular hydrogen bondings were maintained in spite of introducing the hexafluorovaline residues. The dye-release experiment from lecithin vesicle and antimacrobial activity assay also indicated that 8 showed membrane-disturbing activity like gramicidin S, although the activity of 8 was somewhat weaker than gramicidin S.
- Arai, Toru,Imachi, Takashi,Kato, Tamaki,Ogawa, H. Iyehara,Fujimoto, Tsutomu,Nishino, Norikazu
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p. 1383 - 1389
(2007/10/03)
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- Synthesis of Fluorine-Containing Peptides. Analogues of Angiotensin II Containing Hexafluorovaline.
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γ,γ,γ,γ',γ',γ'-Hexafluorovaline and derivatives have been prepared and incorporated into angiotensin II by fragment condensation and solid-phase peptide synthesis.Hexafluorovaline derivatives showed general resistance toward various enzymatic digestions and the tendency to racemize extensively upon carboxyl activation.When the angiotensin II analogues were assayed on rat uterus, 5>AII had 133percent activity, 5>AII was inactive, and 1,DL-Hfv8>AII was a potent inhibitor of angiotensin II in vitro and in vivo.
- Vine, William H.,Hsieh, Kun-hwa,Marshall, Garland R.
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p. 1043 - 1047
(2007/10/02)
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