Department of Environment Sciences, College of Environment, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China.
Curr Microbiol. 2011 Jun;62(6):1767-73. doi: 10.1007/s00284-011-9926-0. Epub 2011 Apr 2.
The role of a single relA/spoT homolog all1549 (designated hereafter as ana-rsh) of the cyanobacterium Anabaena sp. PCC7120 was investigated. The complementation test in Escherichia coli showed that the protein encoded by ana-rsh possesses guanosine tetraphosphate (p)ppGpp-synthase/hydrolase activity. Under laboratory growth conditions, a low level of ppGpp was detected in Anabaena sp. PCC7120 and the loss of ana-rsh was lethal. Amino acid starvation induced ppGpp accumulation to an appropriate level, and nitrogen deficiency did not alter the ppGpp concentration in Anabaena cells. These data suggest that ana-rsh is required for cell viability under normal growth conditions and involved in the (p)ppGpp-related stringent response to amino acid deprivation, but not related to heterocyst formation and nitrogen fixation of Anabaena sp. PCC7120.
对蓝藻鱼腥藻 PCC7120 中的单个 relA/spoT 同源物 all1549（以下简称 ana-rsh）的作用进行了研究。大肠杆菌的互补测试表明，ana-rsh 编码的蛋白具有鸟苷四磷酸（p）ppGpp-合成酶/水解酶活性。在实验室生长条件下，鱼腥藻 PCC7120 中检测到低水平的 ppGpp，并且 ana-rsh 的缺失是致命的。氨基酸饥饿诱导 ppGpp 积累到适当水平，氮缺乏不会改变鱼腥藻细胞中的 ppGpp 浓度。这些数据表明，ana-rsh 在正常生长条件下对细胞存活是必需的，并参与与氨基酸饥饿相关的（p）ppGpp 严格反应，但与鱼腥藻 PCC7120 的异形胞形成和固氮无关。
