Electrochemical and spectroscopic studies on the conformational structure of hemoglobin assembled on gold nanoparticles.
Electrochemical and spectroscopic studies on the conformational structure of hemoglobin assembled on gold nanoparticles.
复制标题
DOI：
10.1021/jp203344u
复制
发表时间：
2011-06
期刊：
影响因子：
--
通讯作者：
Qian Shao;Ping Wu;Piao Gu;Xiaoqing Xu;Hui Zhang;C. Cai
中科院分区：
文献类型：
--
作者：
Qian Shao;Ping Wu;Piao Gu;Xiaoqing Xu;Hui Zhang;C. Cai
蛋白质构象的变化可能与特定的性质有关，例如功能、运输、组装、聚集倾向和潜在的细胞毒性。特别是蛋白质错误折叠与蛋白质介导的疾病密切相关。在本研究中，结合电化学方法和各种光谱技术，包括紫外-可见吸收、荧光、圆二色性（CD）和傅里叶变换红外（FTIR）光谱，详细研究了金纳米颗粒（AuNPs）表面组装引起的血红蛋白（Hb）构象结构的变化。结果表明，通过将Hb组装在AuNPs表面制备的Hb-AuNPs生物共轭体系中的Hb在二级和三级结构水平上都发生了显着的构象变化。 Hb 在 AuNPs 界面上的组装会导致 Hb 结构的扰动，并诱导血红素基团和色氨酸 (Trp) 残基暴露于溶剂，从而导致蛋白质的电子转移速率增强。 Hb-AuNPs 生物共轭体系的定量二阶导数红外和 CD 光谱计算表明，AuNPs 可以诱导 α 螺旋向 β 折叠结构的转变以及蛋白质的去折叠。此外，还证明了 AuNP 的浓度和尺寸对生物共轭体系中 Hb 构象结构变化的影响。这里获得的结果不仅提供了纳米颗粒上血红蛋白分子的详细构象行为，而且还为根据生物大分子的生物学行为分析纳米颗粒的生物安全性建立了框架。
Protein conformational changes may be associated with particular properties such as function, transportation, assembly, tendency to aggregate, and potential cytotoxicity. Protein misfolding, in particular, has been intimately related to protein-mediated diseases. In this study, the conformational structure changes of hemoglobin (Hb) induced by the assembly on gold nanoparticles (AuNPs) surface were studied in detail by a combination of electrochemical method and various spectroscopic techniques including UV-vis absorption, fluorescence, circular dichroism (CD), and Fourier transform infrared (FTIR) spectroscopy. The results indicated that Hb in the Hb-AuNPs bioconjugate system that was prepared by the assembly of Hb on the surface of AuNPs underwent substantial conformational changes both at secondary and tertiary structure level. The assembly of Hb on the boundary surface of AuNPs could result a disturbance of the structure of Hb and induce the exposure of the heme group and tryptophan (Trp) residues to the solvent, leading to the enhancement in the electron transfer rate of the protein. The calculation from quantitative second-derivative infrared and CD spectra of the Hb-AuNPs bioconjugate system showed that AuNPs could induce the conversion of α-helix to β-sheet structures and unfolding of the protein. Moreover, the effects of the concentration and the size of AuNPs on the conformational structure changes of Hb in the bioconjugate system were also demonstrated. The results obtained here not only provide the detailed conformational behavior of Hb molecules on nanoparticles, but also create a framework for analyzing the biosafety of nanoparticles in terms of the biological behavior of biomacromolecules.