Schäffer Christina, Kählig Hanspeter, Christian Rudolf, Schulz Gerhard, Zayni Sonja, Messner Paul
Zentrum für Ultrastrukturforschung und Ludwig Boltzmann-Institut für Molekulare Nanotechnologie, Universität für Bodenkultur, Gregor-Mendel-Str. 33, A-1180 Wien, Austria.
Institut für Organische Chemie, Universität Wien, A-1090 Wien, Austria.
Microbiology (Reading). 1999 Jul;145 ( Pt 7):1575-1583. doi: 10.1099/13500872-145-7-1575.
The diacetamidodideoxymannuronic-acid-containing glycan of Bacillus stearothermophilus NRS 2004/3a with the repeating unit structure [-->4)-beta-D-ManpA2,3(NAc)2-(1-->6)-alpha-D-Glcp-(1-->4)-beta-D-+ ++ManpA2,3 (NAc)2-(1-->3)-alpha-D-GlcpNAc-(1-->], was examined to identify its linkage to the bacterial cell wall. In a previous paper it was suggested that this glycan is covalently linked to the surface layer (S-layer) glycoprotein of that organism. By improved chromatographic techniques (gel permeation over Sephacryl S-1000 SF; C4 reversed-phase HPLC) the diacetamidodideoxyuronic-acid-containing material was completely separated from the S-layer glycoprotein. This implicates only low, if any, specific affinity between these cell-wall components. To obtain sufficient amounts for the chemical characterization of its linkage region, the identical diacetamidodideoxyuronic-acid-containing material was isolated from sonicated cells of that organism by a purification procedure different to that for preparation of S-layers. This method allowed collection of the intact molecule including its linkage region. From the combined results of the chemical characterization and 600 MHz NMR spectroscopy it is proposed that the diacetamidodideoxyuronic-acid-containing glycan chain, consisting of approximately six tetrasaccharide repeating units, is directly linked via a pyrophosphate bridge to carbon 6 of muramic acid residues of the peptidoglycan sacculus. About 20-25% of the muramic acid residues are substituted with these polysaccharide chains. Thus, the diacetamidodideoxyuronic-acid-containing glycan represents a secondary cell-wall polymer of B. stearothermophilus NRS 2004/3a.
对嗜热脂肪芽孢杆菌NRS 2004/3a中含有二乙酰氨基二脱氧甘露糖醛酸的聚糖进行了研究，其重复单元结构为[-->4)-β-D-甘露糖醛酸2,3(NAc)2-(1-->6)-α-D-葡萄糖-(1-->4)-β-D-+++甘露糖醛酸2,3(NAc)2-(1-->3)-α-D-葡萄糖胺-(1-->]，以确定其与细菌细胞壁的连接方式。在之前的一篇论文中提出，这种聚糖与该生物体的表面层（S层）糖蛋白共价连接。通过改进的色谱技术（在Sephacryl S-1000 SF上进行凝胶渗透；C4反相高效液相色谱），将含有二乙酰氨基二脱氧糖醛酸的物质与S层糖蛋白完全分离。这意味着这些细胞壁成分之间即使有亲和力也是很低的。为了获得足够量的物质用于其连接区域的化学表征，通过一种不同于制备S层的纯化程序，从该生物体的超声处理细胞中分离出相同的含有二乙酰氨基二脱氧糖醛酸的物质。这种方法可以收集包括其连接区域在内的完整分子。根据化学表征和600 MHz核磁共振光谱的综合结果，提出由大约六个四糖重复单元组成的含有二乙酰氨基二脱氧糖醛酸的聚糖链通过焦磷酸桥直接连接到肽聚糖囊泡中胞壁酸残基的碳6上。大约20-25%的胞壁酸残基被这些多糖链取代。因此，含有二乙酰氨基二脱氧糖醛酸的聚糖代表了嗜热脂肪芽孢杆菌NRS 2004/3a的一种次要细胞壁聚合物。
