Oxygen-regulated mRNAs for light-harvesting and reaction center complexes and for bacteriochlorophyll and carotenoid biosynthesis in Rhodobacter capsulatus during the shift from anaerobic to aerobic growth

Journal Article · Mon Dec 01 00:00:00 EST 1986 · J. Bacteriol.; (United States)

OSTI ID:6899209

Zhu, Y S; Cook, D N; Leach, F; Armstrong, G A; Alberti, M; Hearst, J E

The stability and regulation by oxygen of mRNAs for the photosynthetic apparatus in Rhodobacter capsulatus have been studied by using proflavin to inhibit transcription and by shifting cells from anaerobic to aerobic conditions. The results from the inhibition experiments show that the mRNA for the light-harvesting LH-II polypeptides (..beta.., ..cap alpha..) is more stable than that for the light-harvesting LH-I polypeptides (..beta.., ..cap alpha..) during anaerobic growth, whereas the mRNAs for the reaction center polypeptides L (RC-L), M (RC-M), and H (RC-H) are less stable than both the LH-I and LH-II mRNAs. When photosynthetic cells were shifted from anaerobic to aerobic conditions, an immediate decrease in the levels of mRNA for the LH-I, LH-II, RC-L, RC-M, and RC-H proteins was observed. The levels of mRNA for the LH-II proteins, however, is more sensitive to oxygen and is reduced faster than the level of mRNA and for the LH-I proteins. These results suggest that oxygen represses the expression of genes coding for the light-harvesting antenna and reaction center complexes and may selectively accelerate the degradation of mRNA for the LH-II proteins. The mRNAs for several enzymes in the bacteriochlorophyll biosynthetic pathway are regulated by oxygen in a similar manner. The authors found that the amounts of mRNAs for carotenoid biosynthetic enzymes, relative to the amounts of mRNAs for LH and RC, increased during the shift from anaerobic to aerobic conditions. They have particularly shown that although the expression of most photosynthetic genes in R. capsulatus is repressed b oxygen, the ctA gene responds to oxygen in an opposite fashion.

• Research Organization: Lawrence Berkeley Lab., CA
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6899209
• Journal Information: J. Bacteriol.; (United States), Vol. 168:3
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BACTERIA
GROWTH
CAROTENOIDS
BIOSYNTHESIS
CHLOROPHYLL
MESSENGER-RNA
BIOCHEMICAL REACTION KINETICS
OXYGEN
RESPONSE MODIFYING FACTORS
PHOTOSYNTHETIC REACTION CENTERS
AEROBIC CONDITIONS
ANAEROBIC CONDITIONS
CHLOROPHYLL-BINDING PROTEINS
GENE REGULATION
PHOTOSYNTHESIS
TRANSCRIPTION
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
ELEMENTS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
KINETICS
MICROORGANISMS
NONMETALS
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
REACTION KINETICS
RNA
SYNTHESIS
TERPENES
550200* - Biochemistry
550700 - Microbiology