Kumar Manish, Chatterji Dipankar
Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
Microbiology (Reading). 2008 Oct;154(Pt 10):2942-2955. doi: 10.1099/mic.0.2008/017806-0.
Cyclic di-GMP (c-di-GMP) plays an important role in bacterial adaptation to enable survival in changing environments. It orchestrates various pathways involved in biofilm formation, changes in the cell surface, host colonization and virulence. In this article, we report the presence of c-di-GMP in Mycobacterium smegmatis, and its role in the long-term survival of the organism. M. smegmatis has a single bifunctional protein with both GGDEF and EAL domains, which show diguanylate cyclase (DGC) and phosphodiesterase (PDE)-A activity, respectively, in vitro. We named this protein MSDGC-1. Deletion of the gene encoding MSDGC-1 did not affect growth and biofilm formation in M. smegmatis, but long-term survival under conditions of nutritional starvation was affected. Most of the proteins that contain GGDEF and EAL domains have been demonstrated to have either DGC or PDE-A activity. To gain further insight into the regulation of the protein, we cloned the individual domains, and tested their respective activities. MSDGC-1, the full-length protein, is required for activity, as its GGDEF and EAL domains are inactive when separated.
环二鸟苷酸（c-di-GMP）在细菌适应环境变化以实现生存方面发挥着重要作用。它协调参与生物膜形成、细胞表面变化、宿主定殖和毒力的各种途径。在本文中，我们报道了耻垢分枝杆菌中环二鸟苷酸的存在及其在该生物体长期存活中的作用。耻垢分枝杆菌有一种具有GGDEF和EAL结构域的单一双功能蛋白，在体外分别表现出二鸟苷酸环化酶（DGC）和磷酸二酯酶（PDE）-A活性。我们将这种蛋白命名为MSDGC-1。编码MSDGC-1的基因缺失并不影响耻垢分枝杆菌的生长和生物膜形成，但在营养饥饿条件下的长期存活受到了影响。大多数含有GGDEF和EAL结构域的蛋白已被证明具有DGC或PDE-A活性。为了进一步深入了解该蛋白的调控机制，我们克隆了各个结构域，并测试了它们各自的活性。全长蛋白MSDGC-1对于活性是必需的，因为其GGDEF和EAL结构域分开时无活性。
