Xie Hui, Becraft Eric J, Baughman Ray H, Dalton Alan B, Dieckmann Gregg R
Department of Chemistry, The University of Texas at Dallas,Texas, 75083-0688, USA.
J Pept Sci. 2008 Feb;14(2):139-51. doi: 10.1002/psc.978.
A series of surfactant peptides were created to evaluate the affinity of aromatic AAs for single-walled carbon nanotubes in the absence of complications from peptide folding or self-association. Each surfactant peptide has a lipidlike architecture, with two Lys residues at the C-terminus as a hydrophilic head, five Val residues to form a hydrophobic tail, and the testing AA at the N-terminus. Raman and CD spectroscopic studies reveal that the surfactant peptides have a large unordered structural component which is independent of peptide concentration, suggesting that the peptides undergo minimal association under experimental conditions, thus removing this interference from interpretation of the peptide/carbon nanotube interactions. A lack of peptide self-association is also indicated by sedimentation equilibrium ultracentrifugation results. Optical spectroscopy of the peptide/carbon nanotube dispersions indicate that among the three aromatic AAs, tryptophan has the highest affinity for carbon nanotubes (both bundled and individual states) when incorporated into a surfactant peptide, while the Tyr-containing peptide is more selective for individual carbon nanotubes. Phe has the lowest overall affinity for carbon nanotubes. Raman spectra of dispersions made with SPF, SPY and SPW display similar types of nanotubes dispersed, although differences in the relative nanotube populations are observed by optical spectroscopy.
设计了一系列表面活性剂肽，以评估在不存在肽折叠或自缔合并发症的情况下，芳香族氨基酸对单壁碳纳米管的亲和力。每个表面活性剂肽都具有类脂结构，在C端有两个赖氨酸残基作为亲水头，五个缬氨酸残基形成疏水尾，测试氨基酸位于N端。拉曼光谱和圆二色光谱研究表明，表面活性剂肽具有很大的无序结构成分，且与肽浓度无关，这表明肽在实验条件下发生的缔合极少，从而消除了这种干扰对肽/碳纳米管相互作用解释的影响。沉降平衡超速离心结果也表明不存在肽自缔合现象。肽/碳纳米管分散体的光谱表明，在三种芳香族氨基酸中，当色氨酸掺入表面活性剂肽时，对碳纳米管（成束和单个状态）的亲和力最高，而含酪氨酸的肽对单个碳纳米管更具选择性。苯丙氨酸对碳纳米管的总体亲和力最低。用SPF、SPY和SPW制备的分散体的拉曼光谱显示，分散的纳米管类型相似，尽管通过光谱观察到相对纳米管数量存在差异。
