A Quantitative, Real-Time Assessment of Binding of Peptides and Proteins to Gold Surfaces
A Quantitative, Real-Time Assessment of Binding of Peptides and Proteins to Gold Surfaces
复制标题
DOI：
10.1002/chem.201001781
复制
发表时间：
2011-01-01
影响因子：
4.3
通讯作者：
Schreiber, Gideon
中科院分区：
文献类型：
--
作者：
Cohavi, Ori;Reichmann, Dana;Schreiber, Gideon
多肽和蛋白质与无机表面的相互作用对天然和人工系统都很重要；然而，对这种相互作用缺乏详细的了解。在这项研究中，我们应用了新的方法来定量测量氨基酸和蛋白质与金表面的结合。实时表面等离子体共振(SPR)测量表明，TEM1-β-内酰胺酶抑制蛋白(BLIP)与金纳米颗粒(NPs)只有微弱的相互作用。然而，三个组氨酸残基与BLIP的融合(~H-BLIP)导致与Au NPs的结合显著增加，当组氨酸尾部延伸到六个组氨酸(6H-BLIP)时，结合进一步增加。进一步增加His残基的数量对结合没有影响。使用连续的(111)织构的Au表面和单晶的(111)取向的平行研究。用椭偏仪、傅里叶变换红外光谱和局域表面等离子体共振(LSPR)光谱进一步证实了这一结果，验证了Au纳米粒子作为模型表面的广泛适用性。对与BLIP融合的所有其他天然氨基酸同源三肽(Cys和Pro除外)的结合评价表明，相对于小的脂肪族和带负电荷的残基，芳香族和带正电荷的残基优先与Au结合，结合速度与结合能力有关。所有融合的结合是不可逆转的。利用Au-NP修饰的SPR芯片对合成的、游离的、可溶的三肽进行SPR测量，证实了这些发现。然而，在这里，结合是可逆的，允许确定与相关斑点融合的结合势相关的结合亲和力。~3H-BLIP与组氨酸三肽(3His)的竞争分析表明，Au结合残基促进了蛋白质在表面的吸附，从而促进了多肽链与Au的不可逆相互作用。用连续介质溶剂模型模拟了氨基酸与Au的结合过程，与实验值吻合较好。这些结果，加上观察到的BLIP融合和游离肽的结合势和动力学，表明了一种与生物蛋白质相互作用明显不同的结合机制。
Interactions of peptides and proteins with inorganic surfaces are important to both natural and artificial systems; however, a detailed understanding of such interactions is lacking. In this study, we applied new approaches to quantitatively measure the binding of amino acids and proteins to gold surfaces. Real-time surface plasmon resonance (SPR) measurements showed that TEM1-beta-lactamase inhibitor protein (BLIP) interacts only weakly with Au nanoparticles (NPs). However, fusion of three histidine residues to BLIP (3H-BLIP) resulted in a significant increase in the binding to the Au NPs, which further increased when the histidine tail was extended to six histidines (6H-BLIP). Further increasing the number of His residues had no effect on the binding. A parallel study using continuous (111)-textured Au surfaces and single-crystalline, (111)-oriented. Au islands by ellipsometry, FTIR, and localized surface plasmon resonance (LSPR) spectroscopy further confirmed the results, validating the broad applicability of Au NPs as model surfaces. Evaluating the binding of all other natural amino acid homo-tripeptides fused to BLIP (except Cys and Pro) showed that aromatic and positively-charged residues bind preferentially to Au with respect to small aliphatic and negatively charged residues, and that the rate of association is related to the potency of binding. The binding of all fusions was irreversible. These findings were substantiated by SPR measurements of synthesized, free, soluble tripeptides using Au-NP-modified SPR chips. Here, however, the binding was reversible allowing for determination of binding affinities that correlate with the binding potencies of the related BLIP fusions. Competition assays performed between 3H-BLIP and the histidine tripeptide (3 His) suggest that Au binding residues promote the adsorption of proteins on the surface, and by this facilitate the irreversible interaction of the polypeptide chain with Au. The binding of amino acids to Au was simulated by using a continuum solvent model, showing agreement with the experimental values. These results, together with the observed binding potencies and kinetics of the BLIP fusions and free peptides, suggest a binding mechanism that is markedly different from biological protein protein interactions.