Glucan and glycogen exist as a covalently linked macromolecular complex in the cell wall of Candida albicans and other Candida species.
Glucan and glycogen exist as a covalently linked macromolecular complex in the cell wall of Candida albicans and other Candida species.
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DOI：
10.1016/j.tcsw.2021.100061
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发表时间：
2021-12
期刊：
影响因子：
--
通讯作者：
Williams DL
中科院分区：
文献类型：
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作者：
Lowman DW;Sameer Al-Abdul-Wahid M;Ma Z;Kruppa MD;Rustchenko E;Williams DL
真菌细胞壁充当生物体与其环境之间的界面。复合碳水化合物是白色念珠菌细胞壁的主要成分，即葡聚糖、甘露聚糖和几丁质。 β-葡聚糖是一种病原体相关分子模式 (PAMP)，由 β-(1 → 3,1 → 6) 连接的吡喃葡萄糖基重复单元组成。这种 PAMP 在真菌结构完整性和免疫识别中发挥着关键作用。糖原是一种 α-(1 → 4,1 → 6)-连接的葡聚糖，是一种细胞内能量储存碳水化合物。我们观察到，在从白色念珠菌 SC5314 中分离 β-葡聚糖的过程中，糖原被共提取。我们假设葡聚糖和糖原可能形成一种大分子物质，将细胞内糖原与细胞壁 β-(1 → 3,1 → 6)-葡聚糖连接起来。为了检验这一假设，我们通过多维核磁共振检查了葡聚糖-糖原提取物，以确定糖原和 β-葡聚糖是否相互关联。 1H NMR 分析证实了大分子中存在糖原和β-葡聚糖。有序扩散光谱 (DOSY) 证实 β-葡聚糖和糖原共扩散，这表明两种聚合物之间存在连接。我们确定这种连接不是通过肽和/或小蛋白质。我们的数据表明，糖原通过 β-(1 → 6) 连接侧链与 β-(1 → 3,1 → 6) 葡聚糖共价连接。我们还发现葡聚糖-糖原复合物存在于 C. dublinensis、C. haemulonii 和 C. auris 中，但不存在于 C. glabrata 或 C. albicans 菌丝葡聚糖中。这些数据表明，葡聚糖和糖原在白色念珠菌和其他念珠菌属物种的细胞壁中形成新型大分子复合物。这种新的、独特的结构扩展了我们对念珠菌属细胞壁的理解。
The fungal cell wall serves as the interface between the organism and its environment. Complex carbohydrates are a major component of the Candida albicans cell wall, i.e., glucan, mannan and chitin. β-Glucan is a pathogen associated molecular pattern (PAMP) composed of β-(1 → 3,1 → 6)-linked glucopyranosyl repeat units. This PAMP plays a key role in fungal structural integrity and immune recognition. Glycogen is an α-(1 → 4,1 → 6)-linked glucan that is an intracellular energy storage carbohydrate. We observed that glycogen was co-extracted during the isolation of β-glucan from C. albicans SC5314. We hypothesized that glucan and glycogen may form a macromolecular species that links intracellular glycogen with cell wall β-(1 → 3,1 → 6)-glucan. To test this hypothesis, we examined glucan-glycogen extracts by multi-dimensional NMR to ascertain if glycogen and β-glucan were interconnected. 1H NMR analyses confirmed the presence of glycogen and β-glucan in the macromolecule. Diffusion Ordered SpectroscopY (DOSY) confirmed that the β-glucan and glycogen co-diffuse, which indicates a linkage between the two polymers. We determined that the linkage is not via peptides and/or small proteins. Our data indicate that glycogen is covalently linked to β-(1 → 3,1 → 6) glucan via the β -(1 → 6)-linked side chain. We also found that the glucan-glycogen complex was present in C. dublinensis, C. haemulonii and C. auris, but was not present in C. glabrata or C. albicans hyphal glucan. These data demonstrate that glucan and glycogen form a novel macromolecular complex in the cell wall of C. albicans and other Candida species. This new and unique structure expands our understanding of the cell wall in Candida species.