Structural determination of the polar glycoglycerolipids from thermophilic bacteria Meiothermus taiwanensis.
The polar glycolipids were isolated from the thermophilic bacteria Meiothermus taiwanensis ATCC BAA-400 by ethanol extraction and purified by Sephadex LH-20 and silica gel column chromatography. The fatty acid composition of O-acyl groups in the glycolipids was obtained by gas chromatography mass spectroscopy analysis on their methyl esters derived from methanolysis and was made mainly of C(15:0) (34.0%) and C(17:0) (42.3%) fatty acids, with the majority as branched fatty acids (over 80%). Removal of O-acyl groups under mild basic conditions provided two glycolipids, which differ only in N-acyl substitution on a hexosamine. Electrospray mass spectroscopy analysis revealed that one has a C(17:0) N-acyl group and the other hydroxy C(17:0) in a ratio of about 1 : 3.5. Furthermore, complete de-lipidation with strong base followed by selective N-acetylation resulted in a homogeneous tetraglycosyl glycerol. The linkages and configurations of the carbohydrate moiety were then elucidated by MS and various NMR analyses. Thus, the major glycolipid from M. taiwanensis ATCC BAA-400 was determined with the following structure: alpha-Galp(1-6)-beta-Galp(1-6)-beta-GalNAcyl(1,2)-alpha-Glc(1,1)-Gro diester, where N-acyl is C(17:0) or hydroxy C(17:0) fatty acid and the glycerol esters were mainly iso- and anteisobranched C(15:0) and C(17:0).
Yang
Feng-Ling
FL
Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
Lu
Chun-Ping
CP
Chen
Chien-Sheng
CS
Chen
Mao-Yen
MY
Hsiao
Hung-Liang
HL
Su
Yeu
Y
Tsay
San-San
SS
Zou
Wei
W
Wu
Shih-Hsiung
SH
D000215:Acylation; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D034301:Deinococcus / Q000737:chemistry* / Q000235:genetics; D008401:Gas Chromatography-Mass Spectrometry; D005989:Glycerides / Q000737:chemistry*; D006017:Glycolipids / Q000737:chemistry*; D008738:Methyl Ethers / Q000032:analysis; D019906:Nuclear Magnetic Resonance, Biomolecular; D021241:Spectrometry, Mass, Electrospray Ionization
D005989:Glycerides; D006017:Glycolipids; D008738:Methyl Ethers