Neu T R, Dengler T, Jann B, Poralla K
Max-Planck-Institute for Immune Biology, Freiburg, Germany.
J Gen Microbiol. 1992 Dec;138(12):2531-7. doi: 10.1099/00221287-138-12-2531.
The primary structure of an emulsion-stabilizing exopolysaccharide from the adhesive, hydrophobic Rhodococcus strain No. 33 was elucidated by NMR spectroscopy, methylation analyses, periodate oxidation and oligosaccharide analyses. The polysaccharide PS-33 consisted of rhamnose, galactose, glucose and glucuronic acid in molar ratios of 2:1:1:1. The main chain contained 3-substituted alpha-D-glucuronic acid linked to the 3-position at alpha-L-rhamnose, in addition to 3-substituted residues of beta-D-galactose and alpha-D-glucose. The alpha-L-rhamnose of the side chain was linked to position 4 of the galactose. In addition, the polysaccharide was O-acetylated, corresponding to one acetyl group per repeating unit. From the results two structural possibilities could be suggested. As the polysaccharide carries hydrophobic groups (methyl of rhamnose/O-acetyl), it is very likely that these are of general significance for the emulsifying activity of polysaccharides. It also seems to be possible that this polysaccharide is at least partially responsible for the hydrophobic cell surface properties of the Rhodococcus strain No. 33 and it may be involved in hydrophobic interactions when adhering to hydrophobic interfaces.
通过核磁共振光谱、甲基化分析、高碘酸盐氧化和寡糖分析，阐明了来自粘性、疏水性红球菌33号菌株的一种乳液稳定胞外多糖的一级结构。多糖PS-33由鼠李糖、半乳糖、葡萄糖和葡萄糖醛酸组成，摩尔比为2:1:1:1。主链除了含有β-D-半乳糖和α-D-葡萄糖的3-取代残基外，还含有连接到α-L-鼠李糖3位的3-取代α-D-葡萄糖醛酸。侧链的α-L-鼠李糖连接到半乳糖的4位。此外，该多糖被O-乙酰化，每个重复单元对应一个乙酰基。根据结果可以提出两种结构可能性。由于该多糖带有疏水基团（鼠李糖的甲基/O-乙酰基），很可能这些基团对多糖的乳化活性具有普遍意义。也有可能这种多糖至少部分地导致了红球菌33号菌株的疏水细胞表面特性，并且在粘附到疏水界面时可能参与疏水相互作用。
