Dash Rupesh, Mukherjee Soumen, Kundu S C
Department of Biotechnology, Indian Institute of Technology, Kharagpur 721302, India.
Int J Biol Macromol. 2006 May 30;38(3-5):255-8. doi: 10.1016/j.ijbiomac.2006.03.001. Epub 2006 Mar 7.
A high molecular weight water-soluble glue protein, sericin was identified in the cocoon peduncle (a strong thread connecting the cocoons to the branches of the tree with a ring) of the tropical tasar silkworm, Antheraea mylitta. The sericin was isolated by 8M urea containing 1% sodium dodecyl sulfate and beta-mercaptoethenol (2%) or by 1% sodium chloride. The protein was purified by gel filtration chromatography. In SDS-PAGE, a single band of approximately 200kDa was detected both in non-reducing and reducing conditions. Amino acid analysis showed that the protein is enriched in glycine and serine. There is a slight difference observed in amino acid composition between the sericin from cocoon peduncle and cocoon of A. mylitta. Secondary structure estimation by circular dichroism spectrometry showed 36.7% beta-sheets, 52.7% random coils, 10.6% turns and no helices.
在热带柞蚕（柞蚕）的茧柄（一种用环将茧与树枝相连的粗线）中鉴定出一种高分子量水溶性胶蛋白——丝胶蛋白。丝胶蛋白通过含有1%十二烷基硫酸钠和β-巯基乙醇（2%）的8M尿素或1%氯化钠进行分离。该蛋白质通过凝胶过滤色谱法进行纯化。在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）中，在非还原和还原条件下均检测到一条约200kDa的单一谱带。氨基酸分析表明，该蛋白质富含甘氨酸和丝氨酸。柞蚕茧柄丝胶蛋白和茧丝胶蛋白的氨基酸组成存在细微差异。通过圆二色光谱法进行的二级结构估计显示，β-折叠占36.7%，无规卷曲占52.7%，转角占10.6%，无螺旋结构。
