Ohgo Kosuke, Bagusat Frank, Asakura Tetsuo, Scheler Ulrich
Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
J Am Chem Soc. 2008 Mar 26;130(12):4182-6. doi: 10.1021/ja710011d. Epub 2008 Feb 29.
In this study we applied Rheo-NMR to investigate the structural change of Bombyx mori silk fibroin in aqueous solution under shear. Monitoring the time dependence of 1H solution NMR spectra of silk fibroin subjected to constant shear strain, signal intensities of random coil decreased suddenly during shear while peaks from beta-sheet structure did not arise in the solution spectra. After these experiments, an aggregate of silk was found in the Couette flow cell and its secondary structure was determined as beta-sheet by 13C solid-state NMR. In conclusion the moderate shear applied here triggered the change in the secondary structure.
在本研究中，我们应用流变核磁共振（Rheo-NMR）来研究家蚕丝素蛋白在水溶液中受剪切时的结构变化。监测丝素蛋白在恒定剪切应变下1H溶液核磁共振谱随时间的变化，在剪切过程中无规卷曲的信号强度突然下降，而溶液谱中未出现β-折叠结构的峰。这些实验之后，在库埃特流动池中发现了丝的聚集体，并用13C固体核磁共振确定其二级结构为β-折叠。总之，这里施加的适度剪切引发了二级结构的变化。
