N-glycosylation in Archaea: on the coordinated actions of Haloferax volcanii AglF and AglM
N-glycosylation in Archaea: on the coordinated actions of Haloferax volcanii AglF and AglM
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DOI：
10.1111/j.1365-2958.2009.07045.x
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发表时间：
2010-02-01
影响因子：
3.6
通讯作者：
Eichler, Jerry
中科院分区：
文献类型：
--
作者：
Yurist-Doutsch, Sophie;Magidovich, Hilla;Eichler, Jerry
像真核生物和细菌一样，古细菌也能进行n -糖基化。在嗜盐古菌中，n -糖基化是由agl基因簇产物介导的。在本报告中，该基因簇被扩展到包括一个额外的序列，aglM，显示参与己糖酸的生物合成，该己糖酸包含在装饰s层糖蛋白的五糖中，这是一种报告H.火山糖蛋白。在不同的生长条件下，aglM转录谱的变化反映了aglF、aglG和aglI转录谱的变化，这些基因的编码证实了H. volcanii n -糖基化途径的参与者，从而支持了H. volcanii n -糖基化起适应作用的假设。纯化后，生化分析显示AglM具有udp -葡萄糖脱氢酶的功能。在与先前鉴定的葡萄糖-1-磷酸尿苷基转移酶AglF的偶联反应中，葡萄糖-1-磷酸和UTP以NAD+依赖的方式生成udp -葡萄糖醛酸。因此，这些实验代表了在体外重建古细菌n -糖基化过程的第一步。
P>Like Eukarya and Bacteria, Archaea are also capable of performing N-glycosylation. In the halophilic archaeon Haloferax volcanii, N-glycosylation is mediated by the products of the agl gene cluster. In the present report, this gene cluster was expanded to include an additional sequence, aglM, shown to participate in the biosynthesis of hexuronic acids contained within a pentasaccharide decorating the S-layer glycoprotein, a reporter H. volcanii glycoprotein. In response to different growth conditions, changes in the transcription profile of aglM mirrored changes in the transcription profiles of aglF, aglG and aglI, genes encoding confirmed participants in the H. volcanii N-glycosylation pathway, thus offering support to the hypothesis that in H. volcanii, N-glycosylation serves an adaptive role. Following purification, biochemical analysis revealed AglM to function as a UDP-glucose dehydrogenase. In a scoupled reaction with AglF, a previously identified glucose-1-phosphate uridyltransferase, UDP-glucuronic acid was generated from glucose-1-phosphate and UTP in a NAD+-dependent manner. These experiments thus represent the first step towards in vitro reconstitution of the archaeal N-glycosylation process.