Novel synthetic (1 → 6)-α-d-mannodisaccharide substrates support processive mannosylation catalysed by the mycobacterial cell envelope enzyme fraction
摘要:
研究人员合成并在霉菌甘露糖基转移酶试验中筛选了三种新的、具有环己基烷基或辛基磺酰基类似琼酮功能的(1-α-6)-δ-D-甘露二糖。2-Cyclohexylethyl (1 â 6)-α-D-Man2 是最佳的受体底物,而磺酰基则大大降低了甘露二糖作为受体的能力。尽管存在这些差异,但质谱分析证实,所有合成甘露二糖苷都能接受多达十个额外的甘露糖单位,也就是说,转移不受琼脂糖类型的影响。本文报告的结果表明,负责连续甘露糖连接的酶是存在于分枝杆菌细胞包膜无细胞系统中的δ-甘露糖基转移酶。
Synthesis, purification and liquid-crystalline behaviour of several alkyl 1-thio-d-glycopyranosides
摘要:
This paper describes the synthesis, purification, and liquid-crystalline behaviour of a series of alkyl 1-thioglycopyranosides. The synthesis of these derivatives was carried out via a Lewis acid mediated coupling of the fully acetylated monosaccharide with an alkanethiol. The choice of the Lewis acid depends on the configuration of AcO-2, The carbohydrate-derived surfactants exhibit thermotropic liquid-crystalline behaviour. The alkyl 1-thioglycopyranosides form the expected smectic A phases upon heating. The clearing temperatures vary with alkyl chain length which is in accordance with the accepted model for the S-A phase of amphiphilic carbohydrate mesogens. For the alkyl 1-thiotalopyranosides, the clearing points are much lower than expected, presumably due to the formation of an intramolecular hydrogen bond in the talose moiety. (C) 1997 Elsevier Science Ltd.
The synthesis of a series of alkyl (having from C6 to C20 aglycones), cyclohexyl, and cyclohexylalkyl alpha-d-mannopyranosides, 6-deoxygenated analogs, thioglycosides, and sulfones derived thereof, is reported. Here, under the in vitro assay conditions used, none of the 15 tested compounds acted as an inhibitor of the mannose transfer catalyzed by the enzymes present in mycobacterial membrane and cell
Synthesis of octyl O- and S-glycosides related to the GPI anchor of Trypanosoma brucei and their in vitro galactosylation by trypanosomal α-galactosyltransferases
作者:T Ziegler
DOI:10.1016/s0008-6215(96)00215-7
日期:1996.12.13
Octyl O- and S-glycosides of mono- to tri-saccharides related to the core structure alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->6)-alpha-D-Manp of the GPI anchor of Trypanosoma brucei have been prepared via regioselective protodesilylation and glycodesilylation of octyl O- and S-glycosides of 2-O-benzoyl-4,6-O-(1,1,3,3-tetraisopropyl-1,3-disiloxane-1,3-diyl)-alpha-D-mannopyranoside. The synthetic saccharides have been used as substrates for enzymatic alpha-galactosylation with membrane fractions of bloodstream forms of T. brucei strain 427 variants MIT at 1.4, MIT at 1.2, and MIT at 1.5, respectively. (C) 1996 Elsevier Science Ltd.