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Title: Molecular Regulation of Photosynthetic Carbon Dioxide Fixation in Nonsulfur Purple Bacteria

Abstract

The overall objective of this project is to determine the mechanism by which a transcriptional activator protein affects CO 2 fixation (cbb) gene expression in nonsulfur purple photosynthetic bacteria, with special emphasis to Rhodobacter sphaeroides and with comparison to Rhodopseudomonas palustris. These studies culminated in several publications which indicated that additional regulators interact with the master regulator CbbR in both R. sphaeroides and R. palustris. In addition, the interactive control of the carbon and nitrogen assimilatory pathways was studied and unique regulatory signals were discovered.

Authors:
 [1]
  1. The Ohio State Univ., Columbus, OH (United States)
Publication Date:
Research Org.:
The Ohio State Univ., Columbus, OH (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1227191
Report Number(s):
FRT-OSU-1111
DOE Contract Number:
FG02-08ER15976
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; molecular regulation; CO2 fixation; CO2 bioconversions; gene expression; transcriptional regulator

Citation Formats

Tabita, Fred Robert. Molecular Regulation of Photosynthetic Carbon Dioxide Fixation in Nonsulfur Purple Bacteria. United States: N. p., 2015. Web. doi:10.2172/1227191.
Tabita, Fred Robert. Molecular Regulation of Photosynthetic Carbon Dioxide Fixation in Nonsulfur Purple Bacteria. United States. doi:10.2172/1227191.
Tabita, Fred Robert. 2015. "Molecular Regulation of Photosynthetic Carbon Dioxide Fixation in Nonsulfur Purple Bacteria". United States. doi:10.2172/1227191. https://www.osti.gov/servlets/purl/1227191.
@article{osti_1227191,
title = {Molecular Regulation of Photosynthetic Carbon Dioxide Fixation in Nonsulfur Purple Bacteria},
author = {Tabita, Fred Robert},
abstractNote = {The overall objective of this project is to determine the mechanism by which a transcriptional activator protein affects CO2 fixation (cbb) gene expression in nonsulfur purple photosynthetic bacteria, with special emphasis to Rhodobacter sphaeroides and with comparison to Rhodopseudomonas palustris. These studies culminated in several publications which indicated that additional regulators interact with the master regulator CbbR in both R. sphaeroides and R. palustris. In addition, the interactive control of the carbon and nitrogen assimilatory pathways was studied and unique regulatory signals were discovered.},
doi = {10.2172/1227191},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2015,
month =
}

Technical Report:

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  • In recent years, it has become evident that nonsulfur purple bacteria use a much wider range of lignin-derived monomers for photosynthetic and aerobic growth than was previously suspected. While aerobic attack on the benzene ring appears to follow patterns common to aerobic pseudomonads, the anaerobic pathway is radically different, and the reductive attack on the ring, first suggested for Rhodopseudomanas palustris growing on benzoate, has now become firmly established. Coenzyme A thioesters are involved in removal of sidechains from complex aromatic acids prior to attack on the ring itself, and also at all stages of degradation of the nucleus upmore » to and including ring opening. Probable intermediates in the ring reduction reactions have been identified both in vivo and in vitro, but characterization of the enzymes and cofactors involved has yet to be achieved. Two aromatic acid CoA ligases have been purified and the corresponding genes cloned and sequenced. A regulatory gene involved in expression of the ligase needed for 4-hydroxybenzoate activation has also been identified and belongs to the cyclic AMP receptor protein family of transcriptional activators.« less
  • The US Department of Energy is concerned with the fate of energy-related materials, including carbon dioxide, in the marine environment. Using laboratory studies, as well as field studies, an attempt was made to understand the molecular regulation of photosynthetic carbon reduction. The objectives were: to determine the mechanism of regulation of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCase) in phytoplankton in response to changes in light fields; and to determine regulation of (RuBPCase) in response to light under nutrient deprivation.
  • The goals of our DOE OMP project are to (1) understand regulation of ribulose bisphosphate carboxylase (RubisCO) in phytoplankton cultures in response to light regime; (2) determine regulation of RubisCO in response to light during nutrient limitation in these cultures; (3) to determine mechanisms of RubisCO regulation in natural populations of phytoplankton on the ocean margins in the Gulf of Mexico and (4) to measure regulation of RubisCO in phytoplankton of the Hatteras System. Two goals are laboratory-based, and two are ship-based.
  • No abstract prepared.
  • The major goal of this project is to determine how microorganisms regulate the assimilation of CO[sup 2] via pathways alternative to the usual Calvin reductive pentose phosphate scheme. In particular, we are interest in the molecular basis for switches in CO[sub 2] metabolic paths. Several earlier studies had indicated that purple nonsulfur photosynthetic bacteria assimilate significant amounts of CO[sub 2] via alternative non-Calvin routes. We have deleted the gene that encodes. RubisCo (ribulose bisphosphate carboxylase/oxygenase) in both the Rhodobacter sphaeroids and Rhodospirillum rubrum. The R. sphaeroides RubisCO deletion strain (strain 16) could not grow under photoheterotrophic conditions with malate asmore » electron donor and CO[sub 2] as the electron acceptor; however the R. rub RubisCO deletion strain (strain I-19) could. Over the past year we have sought to physiologically characterize strain 16PHC. We found that, 16PHC exhibited rates of whole-cell CO[sub 2] fixation which were significantly higher than strain 16. Strain 16PHC could not grow photolithoautotrophically in a CO[sub 2] atmosphere; however, CO[sub 2] fixation catalyzed by photoheterotrophically grown 16PHC was repressed by the addition of DMSO. Likewise, we found that cells initially grown in the presence of DMSO could induce the CO[sub 2] fixation system when DMSO was removed. Thus, these results suggested that both PHC and I-19 could be used to study alternative CO[sub 2] fixation reactions and their significance in R. sphaexoides and R. rubrum.« less