Graphene Oxide Selectively Enhances Thermostability of Trypsin.
Graphene Oxide Selectively Enhances Thermostability of Trypsin.
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DOI：
10.1021/acsami.5b03118
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发表时间：
2015-05
影响因子：
9.5
通讯作者：
K. Yao;P. Tan;Yinchan Luo;Liangzhu Feng;Ligeng Xu;Zhuang Liu;Youyong Li;Rui Peng
中科院分区：
文献类型：
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作者：
K. Yao;P. Tan;Yinchan Luo;Liangzhu Feng;Ligeng Xu;Zhuang Liu;Youyong Li;Rui Peng
在过去的几年里，石墨烯及其衍生物氧化石墨烯(GO)因其在生物技术中的应用而受到广泛的研究。在我们之前的工作中，我们报道了某些聚乙二醇化的GO(Go-pegs)可以选择性地促进胰酶活性并增强其热稳定性。为了进一步探索这一点，我们在这里合成了一系列不同聚乙二醇化程度的GO-peg。酶活性测定表明，GO和GO-PEGS都能保护胰酶，但不能保护胰凝乳蛋白酶免受高温热变性。令人惊讶的是，聚乙二醇化程度越低，保护效果越好，GO以及聚乙二醇化程度最低的GO-聚乙二醇组显示出最高的保护效率(∼在70°C下保留了70%的活性)。荧光光谱分析表明，GO/GO-PEGS与胰酶有很强的相互作用。分子动力学(MD)模拟结果表明，胰蛋白酶是通过其阳离子残基和亲水残基吸附在GO表面的。与GO吸附胰凝乳酶不同的是，GO覆盖了胰凝乳酶的活性部位。高温分子动力学模拟表明，通过与GO的这种相互作用，胰酶的活性部位被GO稳定和保护。我们的工作不仅展示了GO/GO-PEGS作为胰酶高效、选择性调节剂的潜力，而且还提供了GO与特定蛋白质在纳米生物界面上的相互作用机制。
In the past few years, graphene and its derivative, graphene oxide (GO), have been extensively studied for their applications in biotechnology. In our previous work, we reported certain PEGylated GOs (GO-PEGs) can selectively promote trypsin activity and enhance its thermostability. To further explore this, here we synthesized a series of GO-PEGs with varying PEGylation degrees. Enzymatic activity assay shows that both GO and GO-PEGs can protect trypsin, but not chymotrypsin, from thermal denaturation at high temperature. Surprisingly, the lower the PEGylation degree, the better the protection, and GO as well as the GO-PEG with the lowest PEGylation degree show the highest protection efficiency (∼70% retained activity at 70 °C). Fluorescence spectroscopy analysis shows that GO/GO-PEGs have strong interactions with trypsin. Molecular Dynamics (MD) simulation results reveal that trypsin is adsorbed onto the surface of GO through its cationic residues and hydrophilic residues. Different from chymotrypsin adsorbed on GO, the active site of trypsin is covered by GO. MD simulation at high temperature shows that, through such interaction with GO, trypsin's active site is therefore stabilized and protected by GO. Our work not only illustrates the promising potential of GO/GO-PEGs as efficient, selective modulators for trypsin, but also provides the interaction mechanism of GO with specific proteins at the nano-bio interface.