title: Role of the all1549 (ana-rsh) gene, a relA/spoT homolog, of the Cyanobacterium Anabaena sp. PCC7120.
abstract: 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.
authors: Department of Environment Sciences, College of Environment, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China. 306502@ujs.edu.cn
authors: Degang
authors: D
authors: Ning
authors: Yaru
authors: Y
authors: Qian
authors: Xiaogang
authors: X
authors: Miao
authors: Chongwei
authors: C
authors: Wen
mesh_terms: D017033:Anabaena / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D006158:Guanosine Pentaphosphate / Q000378:metabolism; D006159:Guanosine Tetraphosphate / Q000378:metabolism; D008025:Ligases; D009586:Nitrogen Fixation; D011755:Pyrophosphatases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D006159:Guanosine Tetraphosphate; D006158:Guanosine Pentaphosphate; C027627:guanosine-3',5'-bis(diphosphate) 3'-pyrophosphatase; D011755:Pyrophosphatases; D008025:Ligases; C028812:guanosine 3',5'-polyphosphate synthetases