A biochemical correlate of dimorphism in a zygomycete Benjaminiella poitrasii: characterization of purified NAD-dependent glutamate dehydrogenase, a target for antifungal agents
A biochemical correlate of dimorphism in a zygomycete Benjaminiella poitrasii: characterization of purified NAD-dependent glutamate dehydrogenase, a target for antifungal agents
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DOI：
10.1007/s10482-013-9921-5
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发表时间：
2013-07-01
影响因子：
2.6
通讯作者：
Deshpande, M. V.
中科院分区：
文献类型：
--
作者：
Joshi, C. V.;Pathan, E. K.;Deshpande, M. V.
真菌生物体，特别是病原体，在宿主环境中可逆地改变其营养体（Y，单细胞酵母和H，菌丝）形态以存活和增殖。NAD依赖性谷氨酸脱氢酶（NAD-GDH，EC 1.4.1.2）来自非致病性二型放线菌Benjaminiella poitrasii，先前报道是转换过程的重要生化相关物。将酶纯化至均一并表征。它是一种371 kDa的天然分子量蛋白质，由四个相同的亚基组成。动力学研究表明，与其他NAD-GDH不同，它可能作为合成代谢酶，对2-酮戊二酸的亲和力大于对l-谷氨酸的亲和力。化学修饰揭示了单组氨酸和赖氨酸残基参与酶的催化活性。磷酸化和去磷酸化研究表明，NAD-GDH以活性磷酸化形式存在于B菌丝细胞中。普瓦塔西发现实验室合成的两种1，2，3三唑连接的β-内酰胺-胆汁酸缀合物（B18，B20）是纯化的NAD-GDH的有效抑制剂，其也显著影响B中的Y-H转变。普瓦塔西此外，化合物B20在白色念珠菌菌株和解脂耶氏酵母中的Y-H转变期间抑制芽管形成。NAD-GDH作为抗真菌药物的靶点的可能用途进行了讨论。
The fungal organisms, especially pathogens, change their vegetative (Y, unicellular yeast and H, hypha) morphology reversibly for survival and proliferation in the host environment. NAD-dependent glutamate dehydrogenase (NAD-GDH, EC 1.4.1.2) from a non-pathogenic dimorphic zygomycete Benjaminiella poitrasii was previously reported to be an important biochemical correlate of the transition process. The enzyme was purified to homogeneity and characterized. It is a 371 kDa native molecular weight protein made up of four identical subunits. Kinetic studies showed that unlike other NAD-GDHs, it may act as an anabolic enzyme and has more affinity towards 2-oxoglutarate than l-glutamate. Chemical modifications revealed the involvement of single histidine and lysine residues in the catalytic activity of the enzyme. The phosphorylation and dephosphorylation study showed that the NAD-GDH is present in active phosphorylated form in hyphal cells of B. poitrasii. Two of the 1,2,3 triazole linked beta-lactam-bile acid conjugates synthesized in the laboratory (B18, B20) were found to be potent inhibitors of purified NAD-GDH which also significantly affected Y-H transition in B. poitrasii. Furthermore, the compound B20 inhibited germ tube formation during Y-H transition in Candida albicans strains and Yarrowia lipolytica. The possible use of NAD-GDH as a target for antifungal agents is discussed.