AbstractUnderstanding the mechanism of the interaction between inorganic materials and peptides is important for the development of organic/inorganic hybrid materials. The titanium-binding peptide (TBP; Arg1-Lys2-Leu3-Pro4-Asp5-Ala6) has been reported to possess a high binding affinity to SiO2 as well as TiO2 surfaces. Here, we report the binding modes and mechanism of the TBP to SiO2 nanoparticles. To accomplish this objective, we analyzed the binding sites of the TBP to a SiO2 surface and the structure of the TBP bound to the SiO2 using solution NMR spectroscopy. Saturation transfer difference (STD) NMR analysis was performed to identify the TBP sites that interact with the SiO2 surface, and then Arg1 and Asp5 were identified to be in close contact with the SiO2 surface. The structure of the TBP bound to SiO2 was well defined, and the Arg1 and Asp5 side chains face in the same direction. The combination of these results validates that the guanidyl group of Arg1 and the carboxyl group of Asp5 interact electrostatically with the silanol groups SiO− and SiOH2+ on the SiO2 surface, respectively. The binding mode of TBP/SiO2 was found to be different from that of the TBP/TiO2 system, which has been previously reported.Saturation transfer difference (STD) NMR analysis was performed to identify the titanium-binding peptide (TBP) sites that interact with the SiO2 nanoparticle surface, and then Arg1 and Asp5 were identified to be in close contact with the surface. The structure of the TBP bound to SiO2 determined by the NOESY measurement was well defined, and the Arg1 and Asp5 side chains face in the same direction. These results validates that the NH2+ of Arg1 and the COO− of Asp5 interact electrostatically with the SiO− and SiOH2+ on the SiO2 surface, respectively.

中文翻译：

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通过溶液核磁共振光谱研究与 SiO2 纳米颗粒结合的肽的结合位点和结构

摘要 了解无机材料与多肽相互作用的机理对于有机/无机杂化材料的开发具有重要意义。据报道，钛结合肽（TBP；Arg1-Lys2-Leu3-Pro4-Asp5-Ala6）对 SiO2 和 TiO2 表面具有高结合亲和力。在这里，我们报告了 TBP 与 SiO2 纳米颗粒的结合模式和机制。为了实现这一目标，我们使用溶液核磁共振光谱分析了 TBP 与 SiO2 表面的结合位点以及与 SiO2 结合的 TBP 的结构。进行饱和转移差异 (STD) NMR 分析以确定与 SiO2 表面相互作用的 TBP 位点，然后确定 Arg1 和 Asp5 与 SiO2 表面紧密接触。与 SiO2 结合的 TBP 的结构是明确定义的，Arg1 和 Asp5 侧链面向同一方向。这些结果的结合证实了 Arg1 的胍基和 Asp5 的羧基分别与 SiO2 表面上的硅烷醇基 SiO- 和 SiOH2+ 发生静电相互作用。发现 TBP/SiO2 的结合模式与之前报道的 TBP/TiO2 系统的结合模式不同。 进行饱和转移差异 (STD) NMR 分析以识别相互作用的钛结合肽 (TBP) 位点与 SiO2 纳米颗粒表面，然后确定 Arg1 和 Asp5 与表面紧密接触。通过 NOESY 测量确定与 SiO2 结合的 TBP 的结构是明确定义的，并且 Arg1 和 Asp5 侧链面向同一方向。