Using Hydrogen-Deuterium Exchange to Monitor Protein Structure in the Presence of Gold Nanoparticles
Using Hydrogen-Deuterium Exchange to Monitor Protein Structure in the Presence of Gold Nanoparticles
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DOI：
10.1021/jp506506p
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发表时间：
2014-12-11
影响因子：
3.3
通讯作者：
Fitzkee, Nicholas C.
中科院分区：
文献类型：
--
作者：
Wang, Ailin;Vo, Tam;Fitzkee, Nicholas C.
蛋白质功能化金纳米粒子（AuNP）的潜在应用激发了许多表征蛋白质AuNP相互作用的研究。然而，详细结构信息的缺乏阻碍了我们理解 AuNPs 上蛋白质吸附机制的能力。为了确定吸附过程中发生的结构扰动，通过 NMR 测量了两种蛋白质的酰胺质子的氢/氘交换 (HDX)。具体来说，我们测量了 GB3 和泛素这两种特征良好的蛋白质的慢速（5-300 分钟）和快速（10-500 毫秒）H/D 交换率。总体而言，在存在和不存在 AuNP 的情况下，酰胺交换率非常相似，支持吸附的蛋白质在 AuNP 表面上仍然大部分折叠的模型。观察到几个环残基的交换率存在微小差异，这表明二级结构保持相对刚性，而环和表面残基在结合时可能会经历扰动。引人注目的是，其中一些残基与赖氨酸接近，这支持了一个模型，其中正表面残基可能与金纳米粒子结合的柠檬酸盐有利地相互作用。由于这些蛋白质似乎在 AuNP 表面上保持折叠状态，因此这些研究表明，有可能在不使用化学接头的情况下设计功能性的基于 AuNP 的纳米缀合物。
The potential applications of protein-functionalized gold nanoparticles (AuNPs) have motivated many studies characterizing proteinAuNP interactions. However, the lack of detailed structural information has hindered our ability to understand the mechanism of protein adsorption on AuNPs. In order to determine the structural perturbations that occur during adsorption, hydrogen/deuterium exchange (HDX) of amide protons was measured for two proteins by NMR. Specifically, we measured both slow (5-300 min) and fast (10-500 ms) H/D exchange rates for GB3 and ubiquitin, two well-characterized proteins. Overall, amide exchange rates are very similar in the presence and absence of AuNPs, supporting a model where the adsorbed protein remains largely folded on the AuNP surface. Small differences in exchange rates are observed for several loop residues, suggesting that the secondary structure remains relatively rigid while loops and surface residues can experience perturbations upon binding. Strikingly, several of these residues are close to lysines, which supports a model where positive surface residues may interact favorably with AuNP-bound citrate. Because these proteins appear to remain folded on AuNP surfaces, these studies suggest that it may be possible to engineer functional AuNP-based nanoconjugates without the use of chemical linkers.