Abstract：
The amino sugar N-acetyl-d-glucosamine (GlcNAc) is the key constituent of cell wall components and plays an important role in pathogenesis in a wide range of fungi. However, catabolism of GlcNAc has not been studied in basidiomycete fungi. In this study, we identified and characterized a gene cluster essential for GlcNAc utilization in Cryptococcus deneoformans, an environmental human fungal pathogen. The C. deneoformans genome contains a GlcNAc transporter (Ngt1), a GlcNAc kinase (Hxk3), a GlcNAc-6-phosphate deacetylase (Dac1), and a glucosamine-6-phosphate deaminase (Nag1). Their expression levels were highly induced in cultures containing GlcNAc as the sole carbon source, and the corresponding mutants showed severe growth defects in the presence of GlcNAc. Functional and biochemical analyses revealed that HXK3 encodes a novel GlcNAc kinase. Site-directed mutations of conserved residues of Hxk3 indicated that ATP binding and GlcNAc binding are essential for GlcNAc kinase activities. Taken together, the results from this study provide crucial insights into basidiomycete GlcNAc catabolism. IMPORTANCEN-Acetylglucosamine (GlcNAc) is recognized as not only the building block of chitin but also an important signaling molecule in fungi. The catabolic pathway of GlcNAc also plays an important role in vital biological processes in fungi. However, the utilization pathway of GlcNAc in the phylum Basidiomycota, which contains more than 41,000 species, remains unknown. Cryptococcus deneoformans is a representative basidiomycetous pathogen that causes life-threatening meningitis. In this study, we characterized a gene cluster essential for GlcNAc utilization in C. deneoformans and identified a novel GlcNAc kinase. The results of this study provide important insights into basidiomycete GlcNAc catabolism and offer a starting point for revealing its role in pathogenesis.
摘要：
氨基糖N-乙酰-d-葡糖胺(GlcNAc)是细胞壁成分的关键成分,在多种真菌的发病机制中起重要作用。然而,尚未在担子菌真菌中研究GlcNAc的分解代谢。在这项研究中,我们鉴定并表征了一个基因簇，该基因簇对于在新生隐球菌中利用GlcNAc至关重要，环境人类真菌病原体。变性C。基因组包含GlcNAc转运蛋白（Ngt1），GlcNAc激酶（Hxk3），aGlcNAc-6-磷酸脱乙酰酶(Dac1)，和葡糖胺-6-磷酸脱氨酶(Nag1)。它们的表达水平在含有GlcNAc作为唯一碳源的培养物中被高度诱导，相应的突变体在GlcNAc存在下表现出严重的生长缺陷。功能和生化分析显示HXK3编码一种新型GlcNAc激酶。Hxk3的保守残基的定点突变表明ATP结合和GlcNAc结合对于GlcNAc激酶活性是必需的。一起来看,这项研究的结果为担子菌GlcNAc分解代谢提供了重要的见解。IMPORTANCEN-乙酰葡糖胺（GlcNAc）不仅被认为是几丁质的组成部分，而且是真菌中的重要信号分子。GlcNAc的分解代谢途径在真菌的重要生物过程中也起着重要作用。然而,GlcNAc在担子菌门中的利用途径，包含超过41,000种，仍然未知。变性隐球菌是一种代表性的担子菌病原体，可引起威胁生命的脑膜炎。在这项研究中,我们表征了一个基因簇，GlcNAc在假单胞菌中的利用是必不可少的，并鉴定了一个新的GlcNAc激酶。这项研究的结果为担子菌GlcNAc分解代谢提供了重要见解，并为揭示其在发病机理中的作用提供了起点。
