李积胜等《New Phytologist》2023年
论文题目：Persulfidation maintains cytosolic G6PDs activity through changing tetrameric structure and competing cysteine sulfur oxidation under salt stress in Arabidopsis and tomato
论文作者：Xiaofeng Wang, Cong Shi, Yanfeng Hu, Ying Ma, Yuying Yi, Honglei Jia, Fali Li, Haotian Sun, Tian Li, Xiuyu Wang, Tianjinhong Li and Jisheng Li
论文摘要：
Glucose-6-phosphate dehydrogenases (G6PDs) are essential regulators of cellular redox. Hydrogen sulfide (H2S) is a small gasotransmitter that improves plant adaptation to stress; however, its role in regulating G6PD oligomerization to resist oxidative stress remains unknown in plants.
Persulfidation of cytosolic G6PDs was analyzed by mass spectrometry (MS). The structural change model of AtG6PD6 homooligomer was built by chemical cross-linking coupled with mass spectrometry (CXMS). We isolated AtG6PD6C159A and SlG6PDCC155A transgenic lines to confirm the in vivo function of persulfidated sites with the g6pd5,6 background.
Persulfidation occurs at Arabidopsis G6PD6 Cystine (Cys)159 and tomato G6PDC Cys155, leading to alterations of spatial distance between lysine (K)491-K475 from 42.0 Å to 10.3 Å within the G6PD tetramer. The structural alteration occurs in the structural NADP+ binding domain, which governs the stability of G6PD homooligomer. Persulfidation enhances G6PD oligomerization, thereby increasing substrate affinity. Under high salt stress, cytosolic G6PDs activity was inhibited due to oxidative modifications. Persulfidation protects these specific sites and prevents oxidative damage.
In summary, H2S-mediated persulfidation promotes cytosolic G6PD activity by altering homotetrameric structure. The cytosolic G6PD adaptive regulation with two kinds of protein modifications at the atomic and molecular levels is critical for the cellular stress response.
葡萄糖-6-磷酸脱氢酶(G6PDs)是细胞氧化还原的重要调节因子。硫化氢(H2S)是一种小型气体传递素，可以提高植物对逆境的适应能力;然而，其在植物中调控G6PD寡聚以抵抗氧化应激中的作用尚不清楚。
质谱分析胞质G6PD的硫巯基化作用。采用化学交联-质谱联用技术(CXMS)建立了AtG6PD6同聚物的结构变化模型。我们分离AtG6PD6C159A和SlG6PDCC155A转基因系，以g6pd5,6为背景，确认硫巯基化位点在体内的功能。
拟南芥G6PD6胱氨酸(Cys)159和番茄G6PDC Cys155发生硫巯基化，导致G6PD四聚体中赖氨酸(K)491-K475之间的空间距离从42.0 Å改变到10.3 Å。结构改变发生在NADP+结合结构域，控制着G6PD同聚物的稳定性。硫巯基化修饰增强G6PD寡聚，从而增加底物亲和力。在高盐胁迫下，胞质g6pd活性因氧化修饰而受到抑制。硫巯基化保护这些特定的部位，防止氧化损伤。
总之，H2S介导的硫巯基化通过改变同四聚体结构来促进胞质G6PD活性。胞质G6PD在原子和分子水平上的两种蛋白修饰的适应性调控是细胞应激反应的关键。
文章链接：https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.19188