ABSTRACT
New classes of alpha/gamma- and beta/gamma-hybrid peptides have been synthesized with novel 12/10- and 11/13-mixed helical patterns, respectively. The alpha/gamma-peptides were derived from the dipeptide repeats with alternating arrays of l-Ala and gamma-Caa((l)) (C-linked carbo-gamma-amino acid from d-mannose), which generated a new 12/10-mixed helix, for the first time, without a beta-amino acid. The beta/gamma-peptides made from an alternating arrangement of beta-Caa((x)) (C-linked carbo-beta-amino acid) and gamma-Caa((x)) (C-linked carbo-gamma-amino acid from d-xylose), on the other hand, resulted in an unprecedented 11/13-helix. The secondary structures in these peptides have been ascertained from detailed NMR studies, and CD spectroscopy and molecular dynamics investigations provided additional support for the structures derived.
Subject(s)
Amino Acids/chemistry , Peptides/chemistry , Models, Molecular , Nuclear Magnetic Resonance, Biomolecular , Peptides/chemical synthesis , Spectrometry, Mass, Electrospray IonizationABSTRACT
A novel macrocyclic diterpene, jatrophenone, has been isolated from the whole plant of Jatropha gossypifolia. The structure of the compound was established by detailed studies of its one- and two-dimensional (1D and 2D) NMR spectra. The compound possesses significant antibacterial activity.
