Occurrence of an α-galacturonosyl-ceramide in the dioxin-degrading bacterium Sphingomonas wittichii

Abstract

The chemical structure of two glycosphingolipids (GSLs) found in the dioxin-degrading bacterium Sphingomonas wittichii strain RW1 was investigated by means of mass spectrometry and 1 H-nuclear magnetic resonance spectroscopy. One of the GSLs was K-D-glucuronosyl-ceramide, commonly present in Sphingomonas spp., and the other was proved to be K-D-galacturonosyl-ceramide, whose sugar configuration has not been reported before. In both GSLs the ceramide portion was composed of myristic acid or 2-hydroxymyristic acid as the fatty acid, and 2-amino-1,3-octadecanediol or 2-amino-cis-13,14-methylene-1,3-eicosanediol as the dihydrosphingosine. ß

Confirmation of the Anomeric Structure of Galacturonic Acid in the Galacturonosyl‐Ceramide of Sphingomonas yanoikuyae

“…The J 1, 2 value for GalA in GSL-1' sy was 3.0 Hz (Table 1). This value was identical with that of α-GalA in GSL-1' sw (2) and in the same range as that of α-GalA in Proteus lipopolysaccharide (15). Additionally, chemical shift value of GalA H-1 in GSL-1' sy was similar to that of α-GalA in Proteus LPS if the difference of standards was taken into consideration.…”

“…1 H-NMR spectrum of GSL-1' sy ( Fig. 3) was nearly identical with the spectrum of GSL-1' sw from S. wittichii (2), although in the present study tetramethylsilane (TMS) slightly present in the solvents was used as a standard for calibration (0.0 ppm) instead of acetone that was used in the previous study (2). As shown in Fig.…”

“…originated from contaminating GSL-1 sy in GSL-1' sy preparation. The chemical shift value of the H-1 signal shifted to 0.29 ppm higher field than the value (5.17 ppm) in the previous study for GSL-1' sw (2). The difference of these values corresponds to the difference of the standards for calibration (TMS or acetone) in both studies.…”

Glycolipids and phospholipids as natural CD1d-binding NKT cell ligands

“…α-Glucuronosylceramide (GSL-1) was isolated from the cell wall of Sphingomonas capsulate, whereas α-galacturonosylceramide (GSL-1′) was isolated from S. yanoikuyae and S. wittichii (Fig. 5) [55][56][57]. The abundant presence of a family of monoglycosylceramides in the cell wall of Sphingomonas species seems to substitute for LPS.…”

Bacterial glycolipids and analogs as antigens for CD1d-restricted NKT cells

“…These included glycolipids of bacterial origin (compounds 1, 2, 5, and 6), ␣-GalCer analogs modified on the galactose moiety and acyl group (compounds 10-18), and variations of sulfatide (compounds 7-9), the only known promiscuous ligand for CD1 (19). The bacterial glycolipids included those isolated from the outer membrane of Sphingomonas wittichii (20) and glycolipids from Borrelia burgdorferi, the Lyme disease spirochete. CD1d-deficient (CD1d Ϫ/Ϫ ) mice were shown to have impaired host resistance to infection by B. burgdorferi, making its glycolipids attractive compounds for further study as possible natural CD1d antigens (21).…”