Molecular and Crystal Structures of Two Terminally Blocked Tripeptides Corresponding to the 3–5 Sequence of the Peptaibol Antibiotics Antiamoebins

✍ Scribed by Valle, Giovanni ;Crisma, Marco ;Toniolo, Claudio ;Beißwenger, Rudolf ;Rieker, Anton ;Jung, Günther

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 681 KB
• Volume: 1989
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.198919890159

✦ Synopsis

The mycotoxin antiamoebin has recently been shown to be a mixture of at least five closely related pep tide^'^^). Like alamethicins, antiamoebins fall in the class of peptaibol antibiotic^^,^), which are characterized by the presence of several Aib residues and a 1,2-aminoalcohol at the C-terminus. In addition, antiamoebins are shown to have (R)-D-Iva residue(s) in their sequences ' I. Here, we wish to describe the results of a X-ray diffraction analysis of two terminally blocked tripeptides [Ac-(Aibh-OMe . 3 H 2 0 (1) and Ac-(Aibh-(R)-Iva-OMe . H 2 0 (2)],

corresponding to the 3 -5 sequence of antiamoebins. The energies of the stable conformations of the tripeptide 2 have been computed with the program ECEPP/2 and compared to the energy of the crystal-state preferred conformation.