Edebrink P, Jansson P E, Bøgwald J, Hoffman J
Department of Organic Chemistry, Stockholm University, Sweden.
Carbohydr Res. 1996 Jun 21;287(2):225-45. doi: 10.1016/0008-6215(96)00076-6.
The oligosaccharide part of the Vibrio salmonicida (strain NCMB 2262) lipopolysaccharide was isolated by mild acid hydrolysis followed by gel-permeation chromatography. The structure was established mainly by methylation analysis, mass spectrometry, and NMR spectroscopy. It is concluded that the oligosaccharide has the following structure, in which L-alpha-D-Hep p is L-glycero-alpha-D-manno-heptopyranose, D-alpha-D-Hepp is D-glycero-alpha-D-manno-heptopyranose, alpha-D-Fuc p4N is 4-amino-4,6-dideoxy-alpha-D-galactopyranose, alpha-NonA is 5-acetamidino-7-acetamido-3,5,7, 9-tetradeoxy-L-glycero-alpha-D-galacto-nonulosonic acid, BA is (R)-3-hydroxybutanoyl, and PEA is phosphoethanolamine. The substitution pattern of the branching heptosyl residue was deduced from 1H NMR chemical shifts and conformations of the branching region, obtained by molecular modelling. The absolute configuration for NonA was determined by NMR spectroscopy from NOE correlations to the neighbouring sugar and 13C NMR chemical shift data. It could also be shown that assignments of nonulosonic acids with the D-glycero-L-galacto configuration, reported by previous investigators, are erroneous and should be changed to L-glycero-D-galacto. The oligosaccharide is assumed to be linked to the 5-position of a Kdo residue, phosphorylated in the 4-position as observed for other lipopolysaccharides from Vibrionaceae. [formula: see text]
通过温和酸水解，然后进行凝胶渗透色谱法，分离出了杀鲑气单胞菌（菌株NCMB 2262）脂多糖的寡糖部分。其结构主要通过甲基化分析、质谱和核磁共振光谱确定。得出该寡糖具有以下结构，其中L-α-D-Hep p为L-甘油-α-D-甘露庚糖，D-α-D-Hepp为D-甘油-α-D-甘露庚糖，α-D-Fuc p4N为4-氨基-4,6-二脱氧-α-D-吡喃半乳糖，α-NonA为5-脒基-7-乙酰氨基-3,5,7,9-四脱氧-L-甘油-α-D-半乳糖壬糖醛酸，BA为(R)-3-羟基丁酰基，PEA为磷酸乙醇胺。从1H NMR化学位移和通过分子建模获得的分支区域构象推导出分支庚糖基残基的取代模式。通过与相邻糖的NOE相关性和13C NMR化学位移数据的核磁共振光谱确定了NonA的绝对构型。还可以表明，先前研究者报道的具有D-甘油-L-半乳糖构型的壬糖醛酸的归属是错误的，应改为L-甘油-D-半乳糖构型。假定该寡糖与Kdo残基的5位相连，如对弧菌科其他脂多糖所观察到的，在4位磷酸化。[化学式：见正文]
