铁和锰对桑蚕丝蛋白构象转变的影响

采用电感耦合等离子体质谱和原子吸收光谱对桑蚕丝腺体和蚕茧丝中Fe和Mn的含量进行表征, 同时采用拉曼光谱研究Fe(III)和Mn(II)对高浓度再生桑蚕丝蛋白水溶液中丝蛋白构象的影响. 研究结果表明, 桑蚕丝纤维中Fe的含量高于其在丝腺体中的含量, 而Mn的含量则相反. 在丝腺体中, Fe的含量从丝腺体的后部到前部逐渐增加; 但Mn含量的变化趋势与Fe不同, 它在丝腺体中部的含量最低. Fe(III)能够诱导丝蛋白的构象由无规线团和/或螺旋结构向β-折叠转变, 但是Mn(II)对丝蛋白的构象没有明显的影响.

Effect of Fe and Mn on the Conformation Transition of Bombyx mori Silk Fibroin

Inductively coupled plasma mass spectroscopy (ICP-MS) and atomic adsorption spectroscopy (AAS) were applied to determine the Fe and Mn contents in both silk glands and cocoon silks of Bombyx mori silkworms. In the meantime, Raman spectroscopy was used to monitor the effect of Fe(III) and Mn(II) on the conformation changes of silk protein in the concentrated regenerated silk fibroin solutions. The results showed that the Fe content in cocoon silk was higher than that in the silk gland, but the Mn content was on the other way round. In addition, the Fe content was gradually increased from the posterior part to the ante-rior part of the silk gland. However, the Mn content did not exhibit the same tendency as Fe did but showed the lowest value in the middle part of the silk gland. Finally the Raman spectra indicated that Fe(III) was able to induce the conformation transition of silk fibroin from random coil and/or helix conformation to β-sheet but Mn(II) seemed no such an effect.