A RelA-SpoT homolog (Cr-RSH) identified in Chlamydomonas reinhardtii generates stringent factor in vivo and localizes to chloroplasts in vitro.

ABSTRACT: A gene encoding a putative guanosine 3',5'-bispyrophosphate (ppGpp) synthase-degradase, designated Cr-RSH, was identified in the unicellular photosynthetic eukaryote Chlamydomonas reinhardtii. The encoded Cr-RSH protein possesses a putative chloroplast-targeting signal at its NH2-terminus, and translocation of Cr-RSH into chloroplasts isolated from C.reinhardtii was demonstrated in vitro. The predicted mature region of Cr-RSH exhibits marked similarity to eubacterial members of the RelA-SpoT family of proteins. Expression of an NH2-terminal portion of Cr-RSH containing the putative ppGpp synthase domain in a relA, spoT double mutant of Escherichia coli complemented the growth deficits of the mutant cells. Chromatographic analysis of 32P-labeled cellular mononucleotides also revealed that e

SUBMITTER: Kasai K 

PROVIDER: S-EPMC137175 | biostudies-literature | 2002 Nov

REPOSITORIES: biostudies-literature