蚕体内不同丝腺部位丝蛋白溶液结构与性质的研究

Studies on the Structures and Properties of Silk Fibroin Solution in Different Divisions of Silk Gland of Silkworm

采用偏光显微镜研究了蚕体内不同丝腺部位(包括前部、中部和后部)中丝蛋白溶液的性质变化,并采用了拉曼光谱和旋转流变仪对中部丝腺(包括前区、中区及后区)的丝蛋白分子结构和流变性能进行了分析。结果发现:蚕体内只有前部丝腺及中部丝腺前区的丝蛋白溶液具有偏光现象;丝蛋白溶液在由中部丝腺后区向前区流动的过程中,粘度及弹性均逐渐变小,其构象则由无规卷曲逐渐向α-螺旋转变,并进一步形成β-折叠构象。由此表明,在蚕体内中部丝腺前区的丝蛋白溶液很可能已经形成了液晶态结构。

In this paper, the properties of silk fibroin solution from different divisions of silk gland of silkworm （including the anterior, the middle and the posterior divisions） were investigated by polarized microscope. Meantime, Raman spectrum and rotational rheometer were used to analyze the structures and rheological properties of silk fibroin solutions in the different parts of the middle division （including the anterior, the middle and the posterior parts）. It was found that only the anterior division and the anterior part of the middle division showed birefringence. Furthermore, with flowing from the posterior part to the anterior part in the middle division of silkworm, the silk fibroin was gradually transfered from random coil into a-helix conformation and then into B-sheet, the viscosity and elasticity of the silk fibroin solution decreased. These results implied that the liquid crystal state structure had been possibly formed in the anterior part of the middle silk gland of silkworm.