Structural analysis of a novel anionic polysaccharide from Porphyromonas gingivalis strain W50 related to Arg-gingipain glycans
Structural analysis of a novel anionic polysaccharide from Porphyromonas gingivalis strain W50 related to Arg-gingipain glycans
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DOI：
10.1111/j.1365-2958.2005.04871.x
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发表时间：
2005-11-01
影响因子：
3.6
通讯作者：
Curtis, MA
中科院分区：
文献类型：
--
作者：
Paramonov, N;Rangarajan, M;Curtis, MA
牙龈卟啉单胞菌的精氨酸牙龈蛋白酶（RgpsA和B）是一个胞外半胱氨酸蛋白酶家族，是该牙周细菌的重要毒力决定因子。识别糖基化单体RgpAs上的表位的单克隆抗体MAb 1B 5也与牙龈卟啉单胞菌W50的细胞表面多糖交叉反应，表明Arg-牙龈卟啉菌蛋白酶的成熟途径可能与表面碳水化合物的生物合成有关。我们报告了交叉反应阴离子多糖（APS）的纯化和结构表征，它不同于牙龈卟啉单胞菌W50的脂多糖和血清型荚膜多糖。通过1D和2D NMR谱和甲基化分析确定了APS的结构，表明它是一种磷酸化的支链甘露聚糖。主链由α-1，6-连接的甘露糖残基组成，侧链含有不同长度的α-1，2-连接的甘露糖寡糖（1 - 2个糖残基），通过1，2-连接与主链连接。重复单元中的一条侧链含有Man α 1- 2 Man α 1-磷酸，其通过磷连接至2位的骨架甘露糖。APS的去-O-磷酸化消除了交叉反应性，表明Man α 1- 2 Man α 1-磷酸片段形成了MAb 1B 5识别的表位的一部分。这种磷酸化的支链甘露聚糖代表了一种新的多糖，其在免疫学上与Arg-牙龈卟啉菌蛋白酶的翻译后添加相关。
The Arg-gingipains (RgpsA and B) of Porphyromonas gingivalis are a family of extracellular cysteine proteases and are important virulence determinants of this periodontal bacterium. A monoclonal antibody, MAb1B5, which recognizes an epitope on glycosylated monomeric RgpAs also cross-reacts with a cell-surface polysaccharide of P. gingivalis W50 suggesting that the maturation pathway of the Arg-gingipains may be linked to the biosynthesis of a surface carbohydrate. We report the purification and structural characterization of the cross-reacting anionic polysaccharide (APS), which is distinct from both the lipopolysaccharide and serotype capsule polysaccharide of P. gingivalis W50. The structure of APS was determined by 1D and 2D NMR spectroscopy and methylation analysis, which showed it to be a phosphorylated branched mannan. The backbone is built up of alpha-1,6-linked mannose residues and the side-chains contain alpha-1,2-linked mannose oligosaccharides of different lengths (one to two sugar residues) attached to the backbone via 1,2-linkage. One of the side-chains in the repeating unit contains Man alpha 1-2Man alpha 1-phosphate linked via phosphorus to a backbone mannose at position 2. De-O-phosphorylation of APS abolished cross-reactivity suggesting that Man alpha 1-2Man alpha 1-phosphate fragment forms part of the epitope recognized by MAb1B5. This phosphorylated branched mannan represents a novel polysaccharide that is immunologically related to the post-translational additions of Arg-gingipains.