Isolation, structure elucidation, and synthesis of eudistomides A and B, lipopeptides from a Fijian ascidian Eudistoma sp.
Eudistomides A (1) and B (2), two new cyclic peptides, were isolated from a Fijian ascidian Eudistoma sp. These five-residue cystine-linked cyclic peptides are flanked by a C-terminal methyl ester and a 12-oxo- or 12-hydroxy-tetradecanoyl moiety. The complete structures of the eudistomides were determined using a combination of spectroscopic and chemical methods. Chiral HPLC analysis revealed that all five amino acid residues in 1 and 2 had the L-configuration. Total synthesis of eudistomides A (1) and B (2) confirmed the proposed structures. Enantioselective lipase-catalyzed hydrolysis of a mixture of C-35 acetoxy epimers indicated a 35R absolute configuration for 2.
Whitson
Emily L
EL
Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, USA.
Ratnayake
Anokha S
AS
Bugni
Tim S
TS
Harper
Mary Kay
MK
Ireland
Chris M
CM
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D055666:Lipopeptides / Q000737:chemistry* / Q000302:isolation & purification; D019906:Nuclear Magnetic Resonance, Biomolecular; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000302:isolation & purification; D020539:Sequence Analysis, Protein; D053719:Tandem Mass Spectrometry; D014561:Urochordata / Q000737:chemistry*
D055666:Lipopeptides; D010456:Peptides, Cyclic