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Abstract：
Nitric oxide (NO) is a signal molecule in plants and animals. Arabidopsis GSNO reductase1 (AtGSNOR1) catalyzes metabolism of S-nitrosoglutathione (GSNO) which is a major biologically active NO species. The GSNOR1 loss-of-function mutant gsnor1-3 overaccumulates GSNO with inherent high S-nitrosylation level and resistance to the oxidative stress inducer paraquat (1,1\'-dimethyl-4,4\'-bipyridinium dichloride). Here, we report the characterization of dgl1-3 as a genetic suppressor of gsnor1-3. DGL1 encodes a subunit of the oligosaccharyltransferse (OST) complex which catalyzes the formation of N-glycosidic bonds in N-glycosylation. The fact that dgl1-3 repressed the paraquat resistance of gsnor1-3 meanwhile gsnor1-3 rescued the embryo-lethal and post-embryonic development defect of dgl1-3 reminded us the possibility that S-nitrosylation and N-glycosylation crosstalk with each other through co-substrates. By enriching glycoproteins in gsnor1-3 and mass spectrometry analysis, TGG2 (thioglucoside glucohydrolase2) was identified as one of co-substrates with high degradation rate and elevated N-glycosylation level in gsnor1-3 ost3/6. The S-nitrosylation and N-glycosylation profiles were also modified in dgl1-3 and gsnor1-3. Thereby, we propose a linkage between S-nitrosylation and N-glycosylation through co-substrates.
摘要：
一氧化氮（NO）是植物和动物中的信号分子。拟南芥GSNO还原酶1（AtGSNOR1）催化S-亚硝基谷胱甘肽（GSNO）的代谢，GSNO是一种主要的生物活性NO物种。GSNOR1功能丧失突变体gsnor1-3以固有的高S-亚硝基化水平和对氧化应激诱导剂百草枯(1,1'-二甲基-4,4'-联吡啶二氯化物)的抗性过度积累GSNO。这里,我们报道了dgl1-3作为gsnor1-3的遗传抑制因子的特征。DGL1编码寡糖转移(OST)复合物的亚基,其在N-糖基化中催化N-糖苷键的形成。dgl1-3抑制gsnor1-3的百草枯抗性，同时gsnor1-3挽救了dgl1-3的胚胎致死性和胚胎后发育缺陷，这一事实提醒我们S-亚硝基化和N-糖基化通过共底物相互串扰的可能性。通过富集gsnor1-3和质谱分析中的糖蛋白，TGG2(硫代葡萄糖苷葡萄糖氢化酶2)被鉴定为在gsnor1-3ost3/6中具有高降解速率和升高的N-糖基化水平的共底物之一。在dgl1-3和gsnor1-3中也修饰了S-亚硝基化和N-糖基化谱。因此，我们提出了通过共底物在S-亚硝基化和N-糖基化之间的连接。
