Identification and characterization of sericin5 reveals non-cocoon silk sericin components with high ?-sheet content and adhesive strength
Identification and characterization of sericin5 reveals non-cocoon silk sericin components with high ?-sheet content and adhesive strength
复制标题
DOI：
10.1016/j.actbio.2022.07.021
复制
发表时间：
2022-08-31
影响因子：
9.7
通讯作者：
Zhao, Ping
中科院分区：
文献类型：
--
作者：
Guo, Kaiyu;Zhang, Xiaolu;Zhao, Ping
丝胶是真丝纤维表面的一种胶状蛋白质。家蚕中含有四种丝胶，即丝胶1(Ser1)、丝胶2(Ser2)、丝胶3(Ser3)和丝胶4(Ser4)。在本研究中，我们报道了一种新的丝胶，丝胶5(Ser5)，它只存在于无茧丝中。我们描述了家蚕Ser5的序列、外显子-内含子结构和翻译产物。Ser5基因全长约22kb，由16个外显子组成。经SDS-PAGE、Western印迹和LC-MS/MS分析，Ser5蛋白的大小为260 kDa。免疫荧光分析表明，Ser5蛋白与Ser1蛋白共定位于丝胶蛋白层。在转录和翻译水平上检测Ser5的表达模式。系统分析和比较了蚕丝胶的氨基酸组成、重复序列和亲水性。形态观察表明，无茧丝的丝胶含量高于蚕茧丝。圆二色谱表明，无茧丝胶比蚕茧丝胶含有更多的β-折叠结构。此外，我们还发现，天然丝胶的亲水性和粘接强度从内层到外层逐渐增加。本研究加深了我们对蚕茧丝和非蚕茧丝中各种丝胶的表达方式、亲水性、二级结构和粘合性能的了解。
Sericins are glue proteins on the surface of silk fibers. Four sericins have been characterized in silkworm, namely sericin1 (Ser1), sericin2 (Ser2), sericin3 (Ser3), and sericin4 (Ser4). In this study, we report a novel sericin, sericin5 (Ser5), which exists only in non-cocoon silk. We describe the sequence, exon-intron structure, and translation products of Ser5 in Bombyx mori . The Ser5 gene is approximately 22-kb long and comprises 16 exons. Ser5 protein has a size of 260 kDa, as determined by SDS-PAGE, western blot, and LC-MS/MS. Immunofluorescence analysis revealed that Ser5 co-localizes with Ser1 in the sericin layer. The expression pattern of Ser5 was detected at the transcriptional and translational levels. We systematically analyzed and compared the amino acid composition, repeat regions, and hydrophilicity of silkworm sericins. Morphological observations showed that non-cocoon silk had more sericin than cocoon silk. Circular dichroism spectra revealed that non-cocoon silk sericin contained more beta-sheet structures than cocoon silk sericin. In addition, we found that the hydrophilicity and adhesive strength of native sericin increases gradually from the inner layer to the outer layer. This research enhances our understanding of various sericins from cocoon silk and non-cocoon silk with regard to their expression patterns, hydrophilicity, secondary structure and adhesive performances.