Structure of a major glycolipid from Thermus oshimai NTU-063 Original Research Article

The structure of a major glycolipid isolated from the thermophilic bacteria Thermus oshimai NTU-063 was elucidated. The sugar and fatty acid compositions were determined by GC–MS and HPLC analysis on their methanolysis and methylation derivatives, respectively. After removal of both O- and N-acyl groups by alkaline treatment, the glycolipid was converted to a fully acetylated tetraglycosyl glycerol derivative, the structure of which was then determined by NMR spectroscopy (TOCSY, HSQC, HMBC). Thus, the complete structure of the major glycolipid from T. oshimai NTU-063 was established as β-Glcp-(1→6)-β-Glcp-(1→6)-β-GlcpNAcyl-(1→2)-α-Glcp-(1→1)-glycerol diester. The N-acyl groups on the 2-amino-2-deoxy-glucopyranose residue are C15:0 and C17:0 fatty acids, whereas the fatty acids of glycerol diester are more heterogeneous including both straight and branched fatty acids from C15:0 to C18:0.