Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan.
Nanoscale. 2017 May 4;9(17):5389-5393. doi: 10.1039/c7nr01001j.
Clarification of the interactions between carbon nanotubes (CNTs) and proteinogenic amino acids is a key approach to understanding CNT-protein interactions. Previous studies have addressed the mechanism of the physical adsorption of amino acids onto CNTs. However, little is known about their chemical reactions in aqueous solutions. Here, we established dispersant-free systems to clarify intrinsic CNT-thiol interactions. We demonstrated that the redox reaction of CNTs with cysteine, containing a thiol group, leads to disulfide bond formation between cysteine molecules, even under acidic conditions. The generality of the redox reaction is validated using other thiols such as dithiothreitol and glutathione. The present results suggest that structures of proteins and peptides containing free thiol groups are chemically modified and misfolded on CNT surfaces by this disulfide bond formation in biological systems.
阐明碳纳米管 (CNTs) 与蛋白氨基酸之间的相互作用是理解 CNT-蛋白相互作用的关键途径。先前的研究已经解决了氨基酸在 CNT 上物理吸附的机制问题。然而，关于它们在水溶液中的化学反应却知之甚少。在这里，我们建立了无分散剂体系来阐明 CNT-巯基的内在相互作用。我们证明了含巯基的半胱氨酸与 CNT 的氧化还原反应导致半胱氨酸分子之间形成二硫键，即使在酸性条件下也是如此。使用其他巯基，如二硫苏糖醇和谷胱甘肽，验证了该氧化还原反应的普遍性。这些结果表明，在生物体系中，含游离巯基的蛋白质和肽的结构通过这种二硫键的形成在 CNT 表面上发生化学修饰和错误折叠。
