Transcription of oxygen-regulated photosynthetic genes requires DNA gyrase in Rhodobacter capsulatus

Journal Article · Wed Jun 01 00:00:00 EDT 1988 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.85.12.4209· OSTI ID:5365192

Zhu, Yu Sheng; Hearst, J E ^[1]

---

1. Lawrence Berkeley Lab., CA (USA)

The regulation of the photosynthetic genes by DNA supercoiling in Rhodobacter capsulatus has been studied by using gyrase inhibitors in vivo and by measurement of mRNA levels of more than a dozen genes. The results demonstrate that the levels of mRNA for light-harvesting (I,II) and reaction center (L, M, H) proteins, bacteriochlorophyll biosynthetic enzymes, ribulose-bisphosphate carboxylase (EC 4.1.1.39), and the mRNAs from the open reading frames Q and R decreased immediately and dramatically upon addition of novobiocin and coumermycin. In contrast, the mRNAs for carotenoid biosynthetic enzymes, the cytochrome bc{sub 1} complex, and constitutively expressed mRNA under aerobic conditions for light-harvesting I and for reaction center (L, M) proteins are less sensitive to the inhibitors. In accordance with these results, the biosynthesis of bacteriochlorophyll is markedly repressed by gyrase inhibitors novobiocin, coumermycin, nalidixic acid, and oxolinic acid either under anaerobic conditions or during a shift from aerobic to anaerobic conditions. The synthesis of light-harvesting (I, II) bacteriochlorophyll complexes is also inhibited by novobiocin and coumermycin. The kinetics of specific mRNA changes and the differential sensitivity of anaerobic and aerobic genes to the gyrase inhibitors strongly suggest that DNA supercoiling is involved in the differential expression of photosynthetic genes in response to the level of oxygen in R. capsulatus.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5365192
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 85:12; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BACTERIA
BIOCHEMICAL REACTION KINETICS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHLOROPHYLL
DNA HELICASES
ENZYME INHIBITORS
ENZYMES
GENE REGULATION
GENES
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
IN VIVO
KINETICS
MESSENGER-RNA
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHOTOSYNTHETIC REACTION CENTERS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
REACTION KINETICS
RNA
SYNTHESIS
TRANSCRIPTION