The chitoblose-binding protein, DasA, acts as a link between chitin utilization and morphogenesis in Streptomyces coelicolor
The chitoblose-binding protein, DasA, acts as a link between chitin utilization and morphogenesis in Streptomyces coelicolor
复制标题
DOI：
10.1099/mic.0.2007/011940-0
复制
发表时间：
2008-02-01
期刊：
影响因子：
2.8
通讯作者：
Rigali, Sebastien
中科院分区：
文献类型：
--
作者：
Colson, Severine;van Wezel, Gilles P.;Rigali, Sebastien
链霉菌是菌丝土壤细菌，其经历导致气生菌丝孢子的发育程序。作为土壤细菌，链霉菌主要依靠纤维素、木聚糖和甲壳素等天然聚合物来定殖其环境生态位，因此这些多糖可能在监测全球环境营养状况方面发挥关键作用。在这项工作中，我们分析了 DasA（壳二糖 ATP 结合盒转运系统的糖结合成分）在告知细胞环境条件方面的作用，及其在发育开始和确保正确孢子形成中的作用。 dasA 的染色体中断导致碳源依赖性营养停滞表型，除了将初级代谢与发育联系起来的 N-乙酰氨基葡萄糖磷酸转移酶系统 (PTSGIcNAc) 之外，我们还鉴定了第二种 DasR 依赖性糖转运蛋白。在允许孢子形成的条件下，观察到高度异常的孢子和许多过早产生的芽管。虽然 GlcNAc 将链霉菌锁定在营养状态，但细胞外高浓度的 GlcNAc 聚合物几丁质对发育没有影响。显着的区别是由于负责导入 GlcNAc（通过 PTS 进入）和几丁质（通过 DasABC 转运蛋白作为水解产物壳二糖 (GIcNA(C2)) 进入）的转运蛋白不同。提供了一个模型来解释这两种本质上不同的运输系统在发展控制中的作用。
Streptomycetes are mycelial soil bacteria that undergo a developmental programme that leads to sporulating aerial hyphae. As soil-dwelling bacteria, streptomycetes rely primarily on natural polymers such as cellulose, xylan and chitin for the colonization of their environmental niche and therefore these polysaccharides may play a critical role in monitoring the global nutritional status of the environment. In this work we analysed the role of DasA, the sugar-binding component of the chitobiose ATP-binding cassette transport system, in informing the cell of environmental conditions, and its role in the onset of development and in ensuring correct sporulation. The chromosomal interruption of dasA resulted in a carbon-source-dependent vegetative arrest phenotype, and we identified a second DasR-dependent sugar transporter, in addition to the N-acetylglucosamine phosphotransferase system (PTSGIcNAc), that relates primary metabolism to development. Under conditions that allowed sporulation, highly aberrant spores with many prematurely produced germ tubes were observed. While GIcNAc locks streptomycetes in the vegetative state, a high extracellular concentration of the GIcNAc polymer chitin has no effect on development. The striking distinction is due to a difference in the transporters responsible for the import of GIcNAc, which enters via the PTS, and of chitin, which enters as the hydrolytic product chitobiose (GIcNA(C2)) through the DasABC transporter. A model explaining the role of these two essentially different transport systems in the control of development is provided.