Characterization of a Novel Lipid A Containingd-Galacturonic Acid That Replaces Phosphate Residues
Characterization of a Novel Lipid A Containingd-Galacturonic Acid That Replaces Phosphate Residues
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一种含有半乳糖醛酸的新型脂质 A 的表征，可替代磷酸盐残基
DOI：
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发表时间：
2000
影响因子：
4.8
通讯作者：
O. Holst
中科院分区：
文献类型：
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作者：
Barbara M. Plötz;B. Lindner;K. Stetter;O. Holst
根据16 S rRNA系统发育树，超嗜热细菌Aquifex pyrophilus代表了细菌王国中分支最深和最短的物种。我们首次表明，一个生物体，这是遗传古老的基础上，其16 S rRNA和存在于极端条件下，可能含有脂多糖（LPS）。采用改良的苯酚/水法从干燥的细菌中提取LPS。SDS-聚丙烯酰胺凝胶电泳和银染显示梯状模式，这是典型的光滑型LPS（具有O-特异性多糖）。通过基质辅助激光解吸电离质谱法测定LPS群体的分子量。脂A在LPS的温和酸水解后沉淀。通过化学分析、气液色谱-质谱联用、基质辅助激光解吸电离质谱、一维和二维核磁共振谱确定了其完整结构。脂质A由β-（1 → 6）-连接的2，3-二氨基-2，3-二脱氧-d-吡喃葡萄糖（DAG）二糖组成，其酰胺键中各带有两个残基（R）-3-羟基十四烷酸和（R）-3-羟基十六烷酸，酯键中带有一个十八烷酸残基。每个DAG部分携带每个3-羟基十四烷酸和3-羟基十六烷酸的一个残基。在非还原DAG中，十八烷酸连接至3-羟基十四烷酸的3-羟基。每个DAG被一个d-半乳糖醛酸残基取代，该残基连接到还原端的O-1和非还原端的O-4。这种结构代表了一种新型的脂质A。
According to the 16 S rRNA phylogenetic tree, the hyperthermophilic bacterium Aquifex pyrophilus represents the deepest and shortest branching species of the kingdomBacteria. We show for the first time that an organism, which is phylogenetically ancient on the basis of its 16 S rRNA and that exists at extreme conditions, may contain lipopolysaccharide (LPS). The LPS was extracted from dried bacteria using a modified phenol/water method. SDS-polyacrylamide gel electrophoresis and silver stain displayed a ladder-like pattern, which is typical for smooth-form LPS (possessing an O-specific polysaccharide). The molecular masses of the LPS populations were determined by matrix-assisted laser-desorption ionization mass spectrometry. Lipid A was precipitated after mild acid hydrolysis of LPS. Its complete structure was determined by chemical analyses, combined gas-liquid chromatography-mass spectrometry, matrix-assisted laser-desorption ionization mass spectrometry, and one- and two-dimensional NMR spectroscopy. The lipid A consists of a β-(1→6)-linked 2,3-diamino-2,3-dideoxy-d-glucopyranose (DAG) disaccharide carrying two residues each of (R)-3-hydroxytetradecanoic acid and (R)-3-hydroxyhexadecanoic acid in amide linkage and one residue of octadecanoic acid in ester linkage. Each DAG moiety carries one residue of each 3-hydroxytetradecanoic and 3-hydroxyhexadecanoic acid. In the nonreducing DAG, the octadecanoic acid is attached to the 3-hydroxy group of 3-hydroxytetradecanoic acid. Each DAG is substituted by one d-galacturonic acid residue, which is linked toO-1 of the reducing and to O-4 of the nonreducing end. This structure represents a novel type of lipid A.