Isolation and characterization of karlotoxin 1, a new amphipathic toxin from Karlodinium veneficum

The karlotoxins (KmTxs) are a family of compounds produced by the dinoflagellate Karlodinium veneficum which cause membrane permeabilization. The structure of KmTx 1, determined using extensive 2D NMR spectroscopy, is very similar to that of the amphidinols and related compounds, though KmTx I features unique structural modifications of the conserved core region. The structure of KmTx I differs from that reported for KmTx 2, the only other reported karlotoxin to date, in lacking chlorination at its terminal alkene and possessing a hydrophobic arm that is two carbons longer. (C) 2008 Elsevier Ltd. All rights reserved.