Margaritis L H, Hamodrakas S J, Papassideri I, Arad T, Leonard K R
Department of Biochemistry, Cell and Molecular Biology and Genetics, University of Athens, Greece.
Int J Biol Macromol. 1991 Aug;13(4):247-53. doi: 10.1016/0141-8130(91)90081-5.
A low-resolution three-dimensional structure of the crystalline innermost chorionic layer (ICL) of the Hawaiian species Drosophila grimshawi and the Drosophila melanogaster eggshell mutant fs(1)384 has been calculated from electron microscope images of tilted negatively stained specimens. The isolated ICL of Drosophila grimshawi is a three-layer structure, about 36 nm thick, whereas the ICL of Drosophila melanogaster eggshell mutant fs(1)384 is a single layer, about 12 nm thick. Each unit in both crystalline structures includes octamers made up of four heterodimers. Crosslinks between the structural elements, both within and between unit cells form an interconnecting network, apparently important in maintaining the integrity of the layer. A model which may account for the ICL self-assembly formation in vivo and the ICL observed lattice polymorphism is proposed, combining data from the three-dimensional reconstruction work and secondary structure features of the ICL component proteins s36 and s38.
已根据倾斜负染标本的电子显微镜图像，计算出夏威夷物种黑腹果蝇（Drosophila grimshawi）和黑腹果蝇（Drosophila melanogaster）卵壳突变体fs(1)384的最内层绒毛膜层（ICL）的低分辨率三维结构。黑腹果蝇分离出的ICL是一种三层结构，约36纳米厚，而黑腹果蝇卵壳突变体fs(1)384的ICL是单层结构，约12纳米厚。两种晶体结构中的每个单元都包括由四个异二聚体组成的八聚体。结构元件之间的交联，包括晶胞内部和晶胞之间的交联，形成了一个相互连接的网络，这显然对维持该层的完整性很重要。结合三维重建工作的数据以及ICL成分蛋白s36和s38的二级结构特征，提出了一个可能解释ICL在体内的自组装形成以及所观察到的ICL晶格多态性的模型。
