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标题：Aglycon diversity of brain sterylglucosides: structure determination of cholesteryl- and sitosterylglucoside
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作者：Hisako Akiyama ; Kazuki Nakajima ; Yoshiyuki Itoh 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：2016
卷号：57
期号：11
页码：2061-2072
DOI：10.1194/jlr.M071480
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：To date, sterylglucosides have been reported to be present in various fungi, plants, and animals. In bacteria, such as Helicobacter pylori , proton NMR spectral analysis of isolated 1- O -cholesteryl-β- d -glucopyranoside (GlcChol) demonstrated the presence of an α-glucosidic linkage. By contrast, in animals, no detailed structural analysis of GlcChol has been reported, in part because animal-derived samples contain a high abundance of glucosylceramides (GlcCers)/galactosylceramides, which exhibit highly similar chromatographic behavior to GlcChol. A key step in vertebrate GlcChol biosynthesis is the transglucosylation reaction catalyzed by glucocerebrosidase (GBA)1 or GBA2, utilizing GlcCer as a glucose donor. These steps are expected to produce a β-glucosidic linkage. Impaired GBA1 and GBA2 function is associated with neurological disorders, such as cerebellar ataxia, spastic paraplegia, and Parkinson’s disease. Utilizing a novel three-step chromatographic procedure, we prepared highly enriched GlcChol from embryonic chicken brain, allowing complete structural confirmation of the β-glucosidic linkage by ¹H-NMR analysis. Unexpectedly, during purification, two additional sterylglucoside fractions were isolated. NMR and GC/MS analyses confirmed that the plant-type sitosterylglucoside in vertebrate brain is present throughout embryonic development. The aglycon structure of the remaining sterylglucoside (GSX-2) remains elusive due to its low abundance. Together, our results uncovered unexpected aglycon heterogeneity of sterylglucosides in vertebrate brain.
关键词：brain lipids ; cholesterol ; glycolipids ; mass spectrometry ; sterols, glucosylceramide ; matrix-assisted laser desorption/ionization-tandem mass spectrometry