Characterization of the changes in secondary structure and architecture of elastin-mimetic triblock polypeptides during thermal gelation
Characterization of the changes in secondary structure and architecture of elastin-mimetic triblock polypeptides during thermal gelation
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DOI：
10.1021/ma060915j
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发表时间：
2006-10-03
期刊：
影响因子：
5.5
通讯作者：
Gehrke, Stevin H.
中科院分区：
文献类型：
--
作者：
D'Souza, Ajit Joseph M.;Hart, David S.;Gehrke, Stevin H.
振动光谱和光散射研究确定了与弹性蛋白模拟三嵌段(EMT)共聚物凝胶化相关的构象变化。EMT多肽以弹性蛋白的VPGVG重复序列为基础，构建为具有相对疏水的B-嵌段的BAB三嵌段共聚物。激光拉曼光谱和ATR-FTIR光谱探测了与H2O和D2O中的凝胶化相关的二级结构的变化。这些光谱的酰胺I区域表明，稳定网络的相互作用是分子间的β-折叠，网络的很大一部分包含β-转角和无序结构。ATR-FTIR光谱的峰值频移表明，在凝胶过程中，扩展的氢键结构(多聚脯氨酸II类结构)转化为β-片状结构。在低于热转变温度的温度下，通过静态光散射外推的分子量大于单个EMT链。这表明在凝胶化之前存在一些分子组织，因此需要相对温和的变化才能发生分子组装。
Vibrational spectroscopy and light scattering studies identify the conformational changes associated with gelation of elastin-mimetic triblock (EMT) copolymers. The EMT polypeptide is based on the VPGVG repeat of elastin and is constructed as a BAB triblock copolymer with relatively hydrophobic B-blocks. Laser Raman and ATR-FTIR spectroscopies probed changes in secondary structure associated with gelation in H2O and D2O. The amide I regions of these spectra suggest that the network-stabilizing interactions are intermolecular beta-sheets with a significant fraction of the network containing beta-turns and disordered structures. Peak frequency shifts in the ATR-FTIR spectra showed a conversion of extended hydrogen-bonded structures (polyproline II-like structures) to beta-sheets during gelation. Molecular weights extrapolated through static light scattering at temperatures below the thermal transition were greater than for a single EMT chain. This suggests that some molecular organization exists prior to gelation, thus requiring relatively modest changes for molecular assembly to occur.