Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology and Department of Biology, University of Crete, Vasilika Vouton, Heraklion, Crete, Greece.
Cell Microbiol. 2009 May;11(5):719-29. doi: 10.1111/j.1462-5822.2009.01297.x. Epub 2009 Feb 10.
Recent structural studies and analyses of microbial genomes have consolidated the understanding of the structural and functional versatility of coiled-coil domains in proteins from bacterial type III secretion systems (T3SS). Such domains consist of two or more α-helices forming a bundle structure. The occurrence of coiled-coils in T3SS is considerably higher than the average predicted occurrence in prokaryotic proteomes. T3SS proteins comprising coiled-coil domains are frequently characterized by an increased structural flexibility, which may vary from localized structural disorder to the establishment of molten globule-like state. The propensity for coiled-coil formation and structural disorder are frequently essential requirements for various T3SS functions, including the establishment of protein-protein interaction networks and the polymerization of extracellular components of T3SS appendages. Possible correlations between the frequently observed N-terminal structural disorder of effectors and the T3SS secretion signal are discussed. The results for T3SS are also compared with other Gram-negative secretory systems.
最近的结构研究和微生物基因组分析巩固了对细菌 III 型分泌系统（T3SS）中蛋白质卷曲螺旋结构域的结构和功能多样性的理解。这种结构域由两个或多个形成束状结构的α-螺旋组成。T3SS 中卷曲螺旋的出现频率明显高于原核生物蛋白质组中预测的平均出现频率。包含卷曲螺旋结构域的 T3SS 蛋白通常具有更高的结构灵活性，这种灵活性可以从局部结构无序到形成类似无定形球蛋白的状态。卷曲螺旋形成和结构无序的倾向通常是 T3SS 各种功能的必要条件，包括建立蛋白质-蛋白质相互作用网络和 T3SS 附属物的细胞外成分的聚合。还讨论了效应蛋白经常观察到的 N 端结构无序与 T3SS 分泌信号之间的可能相关性。还将 T3SS 的结果与其他革兰氏阴性分泌系统进行了比较。
