Abstract
A Gram-positive actinomycete growing on n-hexadecane secreted a family of anionic glycolipid surfactant homologs. The major homolog, with a molecular weight of 1210.6347, had the formula C58H98O26. Following mild alkaline saponification, 1H and 13C NMR spectroscopy were used to characterize the non-reducing trisaccharide backbone: β-Glcp-(1→3)-α-Glcp-(1⇆1)-α-Glcp ('laminaratrehalose'). Hexanoate, succinate, 3-hydroxyoctanoate, and 3-hydroxydecanoate were found in 3:1:1:1 molar ratio using GC-EIMS analysis of fatty acid methyl esters (FAME) prepared by transesterification. We found that the β-hydroxy acids bore secondary hexanoate chains in 3-O-ester linkage, giving acyloxyacyl anions of appropriate m/z in FABMS and FABMS/MS spectra. COSY, HETCOR, HMBC, and HMQC NMR experiments established the acylation pattern: succinate at C-2 of the terminal α-glucopyranose ring; hexanoate at C-3'' of the β-glucopyranose ring; 3-hexanoyloxyoctanoate and 3-hexanoyloxydecanoate at the 2'- and 4-positions. In FABMS spectra, the homologs flanked the molecular ion by ±14 and ±28 amu, suggesting heterogeneity in acyl chain length. Copyright (C) 1999 Elsevier Science Ltd.
Original language | English (US) |
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Pages (from-to) | 112-123 |
Number of pages | 12 |
Journal | Carbohydrate Research |
Volume | 319 |
Issue number | 1-4 |
DOIs | |
State | Published - Jun 30 1999 |
Externally published | Yes |
Keywords
- Biosurfactant, anionic
- Glycolipid, succinylated trehalose
- Lipooligosaccharide, acyltrehalose
- Lipopolysaccharide, lipid A
- Trehalose oligosaccharide, laminaratrehalose
- Trisaccharide, glucose
ASJC Scopus subject areas
- Analytical Chemistry
- Biochemistry
- Organic Chemistry