Expression of the Synechocystis sp. strain PCC 6803 tRNA sup Glu gene provides tRNA for protein and chlorophyll biosynthesis

Journal Article · Thu Nov 01 00:00:00 EST 1990 · Journal of Bacteriology; (USA)

OSTI ID:5926187

O'Neill, G P; Soell, D ^[1]

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1. Yale Univ., New Haven, CT (USA)

In the cyanobacterium Synechocystis sp. strain PCC 6803 (Synechocystis 6803) {delta}-aminolevulinic acid (ALA), the sole precursor for the synthesis of the porphyrin rings of heme and chlorophyll, is formed from glutamate activated by acylation to tRNA{sup Glu}. We report here that Synechocystis 6803 possesses a single tRNA{sup Glu} gene which was transcribed as monomeric precursor tRNA and matured into the two tRNA{sup Glu} species. They differed in the extent of modification of the first anticodon base, 5-methylaminomethyl-2-thiouridine. The two tRNA species had equivalent capacities to stimulate the tRNA-dependent formation of ALA in Synechocystis 6803 and to provide glutamate for protein biosynthesis in an Escherichia coli-derived translation system. These results are in support of a dual role of tRNA{sup Glu}. The levels of tRNA{sup Glu} were examined by Northern (RNA) blot analysis of cellular RNA and by aminoacylation assays in cultures of Synechocystis 6803 in which the amount of chlorophyll synthesized was modulated over a 10-fold range by various illumination regimens or by the addition of inhibitors of chlorophyll and ALA biosynthesis. In these cultures, the level of tRNA{sup Glu} was always a constant fraction of the total tRNA population, suggesting that tRNA{sup Glu} and chlorophyll levels are regulated independently. In addition, the tRNA{sup Glu} was always fully aminoacylated in vivo.

• OSTI ID: 5926187
• Journal Information: Journal of Bacteriology; (USA), Vol. 172:11; ISSN 0021-9193
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CHLOROPHYLL
BIOSYNTHESIS
PROTEINS
TRANSFER RNA
GENES
CYANOBACTERIA
CARBOXYLIC ACIDS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
RNA
SYNTHESIS
550200* - Biochemistry