Exploring the Residue-Level Interactions between the R2ab Protein and Polystyrene Nanoparticles.
Exploring the Residue-Level Interactions between the R2ab Protein and Polystyrene Nanoparticles.
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探索 R2ab 蛋白和聚苯乙烯纳米颗粒之间残留水平的相互作用。
DOI：
10.1101/2023.08.28.554951
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Fitzkee,NicholasC
中科院分区：
文献类型：
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作者：
Somarathne,RadhaP;Misra,SandeepK;Kariyawasam,ChathuriS;Kessl,JacquesJ;Sharp,JoshuaS;Fitzkee,NicholasC
在生物系统中，蛋白质可以与纳米颗粒结合，形成吸附分子的“冠”。纳米颗粒电晕受到高度关注，因为它影响生物体对纳米材料的反应。了解日冕需要了解表面的蛋白质结构、方向和动力学。最终，需要对纳米颗粒表面上的蛋白质行为进行残基水平的映射，但这种映射很难用传统方法获得。在这里，我们研究了 R2ab 和聚苯乙烯纳米颗粒 (PSNP) 在单个残基水平上的相互作用。 R2ab 是一种来自表皮葡萄球菌的细菌表面蛋白，已知与聚苯乙烯强烈相互作用，导致生物膜形成。我们使用赖氨酸甲基化后的质谱分析和氢氘交换 (HDX) NMR 光谱来了解 R2ab 蛋白如何与不同大小的 PSNP 相互作用。通过赖氨酸甲基化，我们观察到 PSNP 存在时甲基化模式的细微但具有统计学意义的变化，表明蛋白质表面可及性发生了改变。 HDX 测量表明，R2ab 蛋白的某些区域在 PSNP 存在的情况下经历更快的交换速率，表明结合后构象发生变化。这两个结果都支持最近提出的“吸附位”模型，其中吸附的蛋白质由散布着部分结构区域的未折叠锚点组成。我们的数据还强调了使用这些技术表征复杂的蛋白质-纳米粒子相互作用的挑战，例如快速交换率。这项研究在深入了解蛋白质如何响应纳米颗粒表面的同时，强调需要先进的方法来在残留物水平上充分理解这些复杂的相互作用。
In biological systems, proteins can bind to nanoparticles to form a “corona” of adsorbed molecules. The nanoparticle corona is of high interest because it impacts the organism’s response to the nanomaterial. Understanding the corona requires knowledge of protein structure, orientation, and dynamics at the surface. Ultimately, a residue-level mapping of protein behavior on nanoparticle surfaces is needed, but this mapping is difficult to obtain with traditional approaches. Here, we have investigated the interaction between R2ab and polystyrene nanoparticles (PSNPs) at the level of individual residues. R2ab is a bacterial surface protein from Staphylococcus epidermidis and is known to interact strongly with polystyrene, leading to biofilm formation. We have used mass spectrometry after lysine methylation and hydrogen-deuterium exchange (HDX) NMR spectroscopy to understand how the R2ab protein interacts with PSNPs of different sizes. Through lysine methylation, we observe subtle but statistically significant changes in methylation patterns in the presence of PSNPs, indicating altered protein surface accessibility. HDX measurements reveal that certain regions of the R2ab protein undergo faster exchange rates in the presence of PSNPs, suggesting conformational changes upon binding. Both results support a recently proposed “adsorbotope” model, wherein adsorbed proteins consist of unfolded anchor points interspersed with regions of partial structure. Our data also highlight the challenges of characterizing complex protein-nanoparticle interactions using these techniques, such as fast exchange rates. While providing insights into how proteins respond to nanoparticle surfaces, this research emphasizes the need for advanced methods to comprehend these intricate interactions fully at the residue level.