Significance of secondary structure in nanostructure formation and thermosensitivity of polypeptide block copolymers
Significance of secondary structure in nanostructure formation and thermosensitivity of polypeptide block copolymers
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DOI：
10.1039/b809116a
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发表时间：
2008-01-01
期刊：
影响因子：
3.4
通讯作者：
Jeong, Byeongmoon
中科院分区：
文献类型：
--
作者：
Choi, Yun Young;Joo, Min Kyung;Jeong, Byeongmoon
从生物基序中得到的明确的纳米结构控制正在引起材料科学家的注意。我们报告说，L-聚丙氨酸的β-折叠结构在开发纤维状纳米结构以及两亲性聚（乙二醇）-L/或DL-聚丙氨酸二嵌段共聚物的溶胶-凝胶转变中发挥着关键作用。L-异构体经历了从无规卷曲到β-片层，以及随着聚合物浓度增加到纳米纤维的转变，而DL-异构体保持为无规卷曲结构，而没有形成任何特定的纳米结构。在高聚合物浓度下，随着温度的升高，聚合物水溶液经历溶胶-凝胶转变，即所谓的反向热凝胶化。具有预组装β-折叠二级结构的L-异构体促进溶胶-凝胶转变，而不是具有无规卷曲结构的DL-异构体。因此，只有L-异构体在20-40 ℃的生理重要范围内显示出溶胶-凝胶转变。本报告提供了基本信息之间的关系，多肽的分级结构和多肽水溶液的热敏溶胶-凝胶转变。
Well-defined nanostructural control from biological motifs is gaining attention among materials scientists. We are reporting that the beta-sheet structure of L-polyalanine plays a critical role in developing a fibrous nanostructure as well as the sol-to-gel transition of amphiphilic poly(ethylene glycol)-L/or DL-polyalanine diblock copolymers. L-isomers underwent transitions from random coils to beta-sheets, and to nanofibers as the polymer concentration increased, whereas the DL-isomer remained as a random coil structure without developing any specific nanostructure. At high polymer concentrations, the aqueous polymer solutions underwent a sol-to-gel transition as the temperature increased, a so called reverse thermal gelation. The L-isomer with a preassembled beta-sheet secondary structure facilitates the sol-to-gel transition rather than the DL-isomer with a random coil structure. Thus, only the L-isomer showed a sol-to-gel transition in the physiologically important range of 20-40 degrees C. This report provides fundamental information on the relationship between hierarchical structures of polypeptides and the thermosensitive sol-gel transition of the polypeptide aqueous solution.