Tuning supramolecular architectures of KI4K amphiphiles via varying terminal variations
Tuning supramolecular architectures of KI4K amphiphiles via varying terminal variations
复制标题
DOI：
10.1016/j.molliq.2017.09.099
复制
发表时间：
2017-12
影响因子：
6
通讯作者：
Yurong Zhao;Wei Yang;L. Deng;Dong Wang
中科院分区：
文献类型：
--
作者：
Yurong Zhao;Wei Yang;L. Deng;Dong Wang
我们在这里报告如何操纵KI 4K的自组装行为的终端变化。结果表明，无论是超分子结构和相应的二级结构可以调整只是通过终端的变化。由于未封端的单键COOH产生的氢键作用，CH_3CO单键KI_4K单键COOH以扭曲或螺旋状条带为主，宽度在40-50 nm之间，高度为双层。作为比较，纳米管具有更大的宽度，但只有单层壁厚占主导地位的CH 3 CO单键KI 4 K单键CONH 2。对于Fmoc单键KI 4 K单键COOH，空间位阻效应限制了宽度的增长，而π − π堆积作用则促进了初级聚集体沿着高度方向的进一步缔合，从而形成了聚集体束.圆二色谱（CD）和傅里叶变换红外光谱（FTIR）结果表明，CH 3CO单键KI 4K单键COOH和Fmoc单键KI 4K单键COOH均为β-折叠和无规卷曲的混合结构，而CH 3CO单键KI 4K单键CONH 2和NH 2单键KI 4K单键COOH均以无规卷曲结构为主.小角中子散射（SANS）结果表明，CH 3CO单键KI 4K单键COOH和CH 3CO单键KI 4K单键CONH 2都是基本的层状结构，但它们通过不同的途径形成不同形状和尺寸的条带和纳米管。Thioflavin-T（ThT）的荧光强度增强能力可能与溶液中聚集体的数量有关，但与聚集体的形态无关。本研究中涉及的肽为研究单键COOH和Fmoc单键对各种非共价相互作用和最终聚集体形态的贡献提供了简单的分子模型。
We report here how to manipulate the self-assembly behavior of KI4K by the terminal variations. The results demonstrated that both the supramolecular architectures and their corresponding secondary structure can be tuned just by terminal variations. Twisted or helical ribbons with width over the range of 40–50 nm and a bilayed height were dominant for the peptide CH3COsingle bondKI4Ksingle bondCOOH due to the hydrogen bonding interactions resulted from the uncapping single bondCOOH. As a comparison, nanotubes with much larger width but only monolayer wall thickness were dominant for CH3COsingle bondKI4Ksingle bondCONH2. As for Fmocsingle bondKI4Ksingle bondCOOH, the steric hindrance effect can limit the width growth but the π − π stacking interactions can promote further association of the primary aggregate along the height direction to form nanofiber bundles. Both circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) results indicated that the CH3COsingle bondKI4Ksingle bondCOOH and Fmocsingle bondKI4Ksingle bondCOOH adopted a mixture of β-sheet and random coil structure while random coil structure was dominant for both CH3COsingle bondKI4Ksingle bondCONH2and NH2single bondKI4Ksingle bondCOOH. The small angle neutron scattering (SANS) results indicated the basic lamellar structure for both CH3COsingle bondKI4Ksingle bondCOOH and CH3COsingle bondKI4Ksingle bondCONH2but they go through different pathways to form ribbons and nanotubes with varied shape and size. The Thioflavin-T (ThT) results indicated their abilities to enhance ThT fluorescence intensity was possibly correlated with the amount of aggregates in solutions except for the aggregate morphologies. The peptides involved in the present study provide simple molecular models for the investigation of both single bondCOOH and Fmocsingle bond in contribution to varied non-covalent interactions and the final aggregate morphologies.