a Faculty of Advance Science and Technology, Department of Nanotechnology , Islamic Azad University (IAUPS) , Pharmaceutical Sciences Branch, Tehran , Iran.
b Biology Department , Islamic Azad University , Tehran Medical Sciences Branch, Tehran , Iran.
J Biomol Struct Dyn. 2017 Sep;35(12):2565-2577. doi: 10.1080/07391102.2016.1222972. Epub 2016 Sep 15.
Herein, the interaction of iron nanoparticle (Fe-NP) with cytochrome c (Cyt c) was investigated, and a range of techniques such as dynamic light scattering (DLS), zeta potential measurements, static and synchronous fluorescence spectroscopy, near and far circular dichroism (CD) spectroscopy, and ultraviolet-visible (UV-vis) spectroscopy were used to analyze the interaction between Cyt c and Fe-NP. DLS and zeta potential measurements showed that the values of hydrodynamic radius and charge distribution of Fe-NP are 83.95 ± 3.7 nm and 4.5 ± .8 mV, respectively. The fluorescence spectroscopy results demonstrated that the binding of Fe-NP with Cyt c is mediated by hydrogen bonds and van der Waals interactions. Also Fe-NP induced conformational changes in Cyt c and reduced the melting temperature value of Cyt c from 79.18 to 71.33°C. CD experiments of interaction between Fe-NP and Cyt c revealed that the secondary structure of Cyt c with the dominant α-helix structures remained unchanged whereas the tertiary structure and heme position of Cyt c are subjected to remarkable changes. Absorption spectroscopy at 695 nm revealed that Fe-NP considerably disrupt the Fe…S(Met80) bond. In addition, the UV-vis experiment showed the peroxidase-like activity of Cyt c upon interaction with Fe-NP. Hence, the data indicate the Fe-NP results in unfolding of Cyt c and subsequent peroxidase-like activity of denatured species. It was concluded that a comprehensive study of the interaction of Fe-NP with biological system is a crucial step for their potential application as intracellular delivery carriers and medicinal agents.
本文研究了铁纳米颗粒（Fe-NP）与细胞色素 c（Cyt c）的相互作用，并采用动态光散射（DLS）、zeta 电位测量、静态和同步荧光光谱、近远圆二色（CD）光谱和紫外-可见（UV-vis）光谱等一系列技术来分析 Cyt c 与 Fe-NP 之间的相互作用。DLS 和 zeta 电位测量结果表明，Fe-NP 的水动力半径和电荷分布值分别为 83.95±3.7nm 和 4.5±0.8mV。荧光光谱结果表明，Fe-NP 与 Cyt c 的结合是通过氢键和范德华相互作用介导的。此外，Fe-NP 诱导 Cyt c 构象发生变化，使 Cyt c 的熔点值从 79.18°C降低至 71.33°C。Fe-NP 与 Cyt c 相互作用的 CD 实验表明，Cyt c 的二级结构保持不变，仍以主导的α-螺旋结构为主，但其三级结构和血红素位置发生了显著变化。695nm 处的吸收光谱表明，Fe-NP 显著破坏了 Fe…S（Met80）键。此外，UV-vis 实验表明，Cyt c 在与 Fe-NP 相互作用后表现出过氧化物酶样活性。因此，数据表明 Fe-NP 导致 Cyt c 展开，并随后使变性物种表现出过氧化物酶样活性。综上所述，对 Fe-NP 与生物体系相互作用进行综合研究是将其作为细胞内递药载体和药物应用的关键步骤。
