Interaction between Silver Nanoparticles and Two Dehydrogenases: Role of Thiol Groups
Interaction between Silver Nanoparticles and Two Dehydrogenases: Role of Thiol Groups
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DOI：
10.1002/smll.201900860
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发表时间：
2019-07-01
期刊：
影响因子：
13.3
通讯作者：
Li, Wei
中科院分区：
文献类型：
--
作者：
Jiang, Hong Sheng;Zhang, Yizhi;Li, Wei
广泛使用的银纳米颗粒 (AgNP) 很容易接触生物体液，然后被蛋白质包围。然而，人们对 AgNP 和蛋白质之间的相互作用知之甚少。选择两种脱氢酶，3-磷酸甘油醛脱氢酶（GAPDH）和苹果酸脱氢酶（MDH）来研究这些相互作用。与这些酶的硫醇基团结合的银显着减少了可用的游离硫醇的数量。在 AgNP 和 Ag+ 处理中均观察到酶活性的剂量依赖性抑制。根据抑制 50% 活性所需的浓度，GAPDH 和 MDH 对 Ag+ 的敏感度比对 AgNP 的敏感度高 24-30 倍，这表明测得的含有 AgNP 的 4.2% Ag+ 可能是酶抑制的原因。 GAPDH 的活性位点上有硫醇基团，比 MDH 对 Ag 更敏感，显示出许多硫醇基团，但活性位点上没有硫醇基团，这表明活性位点上的硫醇基团强烈决定了酶对 AgNPs 的敏感性。相比之下，圆二色光谱的显着变化表明，AgNPs 处理下 MDH 的整体二级结构比 GAPDH 发生了更大的改变。总之，这项研究表明，硫醇基团及其在这些脱氢酶上的位置对于 AgNP 的效果至关重要。
Widely used silver nanoparticles (AgNPs) are readily accessible to biological fluids and then surrounded by proteins. However, interactions between AgNPs and proteins are poorly understood. Two dehydrogenases, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and malate dehydrogenase (MDH), are chosen to investigate these interactions. Ag bound to thiol groups of these enzymes significantly decreases the number of free thiols available. Dose-dependent inhibition of enzyme activities is observed in both AgNPs and Ag+ treatments. Based on the concentration required to inhibit 50% activity, GAPDH and MDH are 24-30 fold more sensitive to Ag+ than to AgNPs suggesting that the measured 4.2% Ag+ containing AgNPs can be responsible for the enzymes inhibition. GAPDH, with a thiol group in its active site, is more sensitive to Ag than MDH, displaying many thiol groups but none in its active site, suggesting that thiol groups at the active site strongly determines the sensitivity of enzymes toward AgNPs. In contrast, the dramatic changes of circular dichroism spectra show that the global secondary structure of MDH under AgNPs treatment is more altered than that of GAPDH. In summary, this study shows that the thiol groups and their location on these dehydrogenases are crucial for the AgNPs effects.