Prev. Article Next Article Table of Contents

Article

Lobocyclamides A−C, Lipopeptides from a Cryptic Cyanobacterial Mat Containing Lyngbya confervoides

Supporting Info

John B. MacMillan, Michael A. Ernst-Russell, Jeffrey S. de Ropp, and Tadeusz F. Molinski*

Department of Chemistry, One Shields Avenue, University of California, Davis, California 95616

J. Org. Chem., 2002, 67 (23), pp 8210–8215

DOI: 10.1021/jo0261909

Publication Date (Web): October 23, 2002

To whom correspondence should be addressed. Tel: 530 752 6358. Fax: 530 752 8995.

, tfmolinski@ucdavis.edu

Abstract

The structures of lipopeptides lobocyclamides A (1), B (2), and C (3) were solved using a combination of mass spectrometry, 2D NMR spectroscopy, and degradative analysis. Lobocyclamides B and C are the first peptides reported with the unusual amino acid 4-hydroxythreonine and also incorporate the rare homologous long-chain β-amino acids 3-aminooctanoic acid and 3-aminodecanoic acid, respectively. The absolute configurations of the amino acid residues in each compound were assigned, after acid hydrolysis, by either direct chiral HPLC comparison with authentic standards or by prior derivatization by Marfey's method and reversed-phase HPLC. Both compounds exhibited moderate antifungal activity against a panel of Candida spp., including two fluconazole-resistant strains. When tested as a mixture, lobocyclamides A and B displayed synergistic in vitro antifungal activity, a phenomenon noted earlier for the related peptides laxaphycins A and B.

View: Full Text HTML | Hi-Res PDF