Electrostatic Interactions and Protein Competition Reveal a Dynamic Surface in Gold Nanoparticle-Protein Adsorption.
Electrostatic Interactions and Protein Competition Reveal a Dynamic Surface in Gold Nanoparticle-Protein Adsorption.
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DOI：
10.1021/acs.jpcc.6b08469
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发表时间：
2016-10-27
影响因子：
3.7
通讯作者：
Fitzkee, Nicholas C.
中科院分区：
文献类型：
--
作者：
Wang, Ailin;Perera, Y. Randika;Davidson, Mackenzie B.;Fitzkee, Nicholas C.
金纳米颗粒-（AuNP-）蛋白质缀合物在广泛的诊断和治疗应用中是潜在有用的，但是同时吸附多种蛋白质到AuNP表面上的物理基础仍然知之甚少。在这里，我们调查的贡献，静电相互作用的蛋白质-金纳米粒子结合通过研究两种蛋白质，GB 3和泛素的pH依赖性结合行为。对于这两种蛋白质，结合到15 nm柠檬酸盐包被的金纳米粒子密切跟踪使用标准pKa值预测的净电荷，并观察到一个显着减少结合时，赖氨酸残基被化学甲基化。这表明碱性残基的簇参与结合，并且使用该假设，我们模拟由AuNP结合诱导的pKa位移。然后，我们采用了一种新的NMR为基础的方法来监测在不同的pH值下，在原位GB 3和泛素之间的结合竞争。根据我们的模型，核磁共振测量结果表明，净电荷，结合缔合常数，和每个蛋白质的大小在蛋白质吸附的不同阶段发挥不同的作用。当柠檬酸盐包被的AuNP和蛋白质第一次相互作用时，净电荷似乎占主导地位。然而，随着柠檬酸盐分子被蛋白质取代，表面化学发生变化，结合的能量学变得更加复杂。在这种情况下，我们观察到GB 3能够在中间时间尺度上取代泛素，即使它具有较低的净电荷。这里开发的结合热力学模型可能是预测生物流体（如血浆）中结合行为的第一步。
Gold nanoparticle– (AuNP–) protein conjugates are potentially useful in a broad array of diagnostic and therapeutic applications, but the physical basis of the simultaneous adsorption of multiple proteins onto AuNP surfaces remains poorly understood. Here, we investigate the contribution of electrostatic interactions to protein–AuNP binding by studying the pH-dependent binding behavior of two proteins, GB3 and ubiquitin. For both proteins, binding to 15-nm citrate-coated AuNPs closely tracks with the predicted net charge using standard pKa values, and a dramatic reduction in binding is observed when lysine residues are chemically methylated. This suggests that clusters of basic residues are involved in binding, and using this hypothesis, we model the pKa shifts induced by AuNP binding. Then, we employ a novel NMR-based approach to monitor the binding competition between GB3 and ubiquitin in situ at different pH values. In light of our model, the NMR measurements reveal that the net charge, binding association constant, and size of each protein play distinct roles at different stages of protein adsorption. When citrate-coated AuNPs and proteins first interact, net charge appears to dominate. However, as citrate molecules are displaced by protein, the surface chemistry changes, and the energetics of binding becomes far more complex. In this case, we observed that GB3 is able to displace ubiquitin at intermediate time scales, even though it has a lower net charge. The thermodynamic model for binding developed here could be the first step toward predicting the binding behavior in biological fluids, such as blood plasma.
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影响因子：
15
作者：
Ceccon A;Tugarinov V;Bax A;Clore GM
通讯作者：
Clore GM
影响因子：
3.9
作者：
Asuri, Prashanth;Bale, Shyam Sundhar;Dordick, Jonathan S.
通讯作者：
Dordick, Jonathan S.
影响因子：
17.1
作者：
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通讯作者：
Puntes, Victor
影响因子：
3.9
作者：
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Yin, Yadong
影响因子：
17.1
作者：
Ivanov, Michael R.;Bednar, Heidi R.;Haes, Amanda J.
通讯作者：
Haes, Amanda J.