Genetic and structural validation of phosphomannomutase as a cell wall target in Aspergillus fumigatus
Genetic and structural validation of phosphomannomutase as a cell wall target in Aspergillus fumigatus
复制标题
烟曲霉细胞壁靶标磷酸甘露糖变位酶的遗传和结构验证
DOI：
10.1111/mmi.14706
复制
发表时间：
2021-03-01
影响因子：
3.6
通讯作者：
van Aalten, Daan M. F.
中科院分区：
文献类型：
--
作者：
Zhang, Yuanwei;Fang, Wenxia;van Aalten, Daan M. F.
烟曲霉菌是一种机会性霉菌，可导致免疫功能低下患者发生严重危及生命的真菌感染。细胞壁是由葡聚糖、几丁质和半乳甘露聚糖组成的基本结构，被认为是开发抗真菌药物的靶点。核苷酸糖供体GDP-甘露糖（GDP-Man）是半乳甘露聚糖、糖基磷脂酰肌醇（GPI）锚、糖脂和蛋白质糖基化的生物合成所必需的。从果糖-6-磷酸开始，GDP-Man通过磷酸甘露糖异构酶、磷酸甘露糖变位酶（Pmm）和GDP-甘露糖焦磷酸化酶的顺序作用产生。在这里，我们使用异核体拯救和基因敲低的方法证明，磷酸甘露变位酶编码基因在A。烟曲霉毒素（pmmA）是生存所必需的。pmmA的表达减少与显著的形态学缺陷相关，包括延迟的萌发、生长、减少的分生孢子和异常极性。此外，敲低菌株表现出改变的细胞壁组织和对细胞壁扰动剂的敏感性。通过求解A.在烟曲霉磷酸甘露变位酶（AfPmmA）中，当与人直向同源物相比时，我们鉴定了活性位点附近的非保守取代。总之，这项工作为开发AfPmmA作为潜在的抗真菌靶点提供了遗传和结构基础。
Aspergillus fumigatus is an opportunistic mold responsible for severe life-threatening fungal infections in immunocompromised patients. The cell wall, an essential structure composed of glucan, chitin, and galactomannan, is considered to be a target for the development of antifungal drugs. The nucleotide sugar donor GDP-mannose (GDP-Man) is required for the biosynthesis of galactomannan, glycosylphosphatidylinositol (GPI) anchors, glycolipid, and protein glycosylation. Starting from fructose-6-phosphate, GDP-Man is produced by the sequential action of the enzymes phosphomannose isomerase, phosphomannomutase (Pmm), and GDP-mannose pyrophosphorylase. Here, using heterokaryon rescue and gene knockdown approaches we demonstrate that the phosphomannomutase encoding gene in A. fumigatus (pmmA) is essential for survival. Reduced expression of pmmA is associated with significant morphological defects including retarded germination, growth, reduced conidiation, and abnormal polarity. Moreover, the knockdown strain exhibited an altered cell wall organization and sensitivity toward cell wall perturbing agents. By solving the first crystal structure of A. fumigatus phosphomannomutase (AfPmmA) we identified non-conservative substitutions near the active site when compared to the human orthologues. Taken together, this work provides a genetic and structural foundation for the exploitation of AfPmmA as a potential antifungal target.