Liu Huiqing, Qiao Haiyan, Krajcikova Daniela, Zhang Zhe, Wang Hongda, Barak Imrich, Tang Jilin
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning University of Petroleum & Chemical Technology, Fushun 113001, PR China.
J Struct Biol. 2016 Aug;195(2):245-251. doi: 10.1016/j.jsb.2016.06.010. Epub 2016 Jun 15.
The spore of Bacillus subtilis, a dormant type of cell, is surrounded by a complex multilayered protein structure known as the coat. It is composed of over 70 proteins and essential for the spore to withstand extreme environmental conditions and allow germination under favorable conditions. However, understanding how the properties of the coat arise from the interactions among all these proteins is an important challenge. Moreover, many specific protein-protein interactions among the coat proteins are crucial for coat assembly. In this study, atomic force microscopy (AFM) based single molecule force spectroscopy (SMFS) was applied to investigate the interaction as a dynamic process between two morphogenetic coat proteins, CotE and CotZ. The unbinding force and kinetic parameters characterizing the interaction between CotE and CotZ were obtained. It is found that there is a strong affinity between CotE and CotZ. Furthermore, the assembly behaviors of CotE and CotZ, individually or in combination, were studied by AFM at solid-liquid interfaces. Our results revealed that CotE-CotZ assembly is dependent on their molar ratios and the interaction between CotE and CotZ involves in the CotE-CotZ assembly.
枯草芽孢杆菌的孢子是一种休眠型细胞，被一种称为外壳的复杂多层蛋白质结构所包围。它由70多种蛋白质组成，对于孢子耐受极端环境条件并在有利条件下萌发至关重要。然而，理解外壳的特性如何由所有这些蛋白质之间的相互作用产生是一项重大挑战。此外，外壳蛋白之间许多特定的蛋白质 - 蛋白质相互作用对于外壳组装至关重要。在本研究中，基于原子力显微镜（AFM）的单分子力谱（SMFS）被用于研究两种形态发生外壳蛋白CotE和CotZ之间作为动态过程的相互作用。获得了表征CotE和CotZ之间相互作用的解离力和动力学参数。发现CotE和CotZ之间有很强的亲和力。此外，通过AFM在固 - 液界面研究了CotE和CotZ单独或组合的组装行为。我们的结果表明，CotE - CotZ组装取决于它们的摩尔比，并且CotE和CotZ之间的相互作用参与了CotE - CotZ组装。
