This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Meyer, J Articles by Vignais, P M Search for Related Content PubMed PubMed Citation Articles by Meyer, J Articles by Vignais, P M

Effect of light nitrogenase function and synthesis in Rhodopseudomonas capsulata.

ABSTRACT

The metabolic versatility of the purple nonsulfur photosynethetic bacterial permits the expression of either a phototrophic or a dark aerobic mode of growth. These organism also possess nitrogenase activity which may function under semiaerboic conditions. On the basis of these important properties, the light dependence of nitrogenase function and synthesis in Rhodopseudomonas capsulata was investigated. Nitrogenase activity was strictly dependent on light; no activity was observed in the dark, even when energy (ATP) was supplied by oxidative phosphorylation. It was concluded that the low-potential reducing agent required by the nitrogenase-catalyzed reaction could only be generated by a photochemical reaction. Nitrogenase biosynthesis was also largely dependent on light; however, a small amount of synthesis was observed in resting cells incubated in the dark. Resting cells prepared from dark-grown cultures synthesized nitrogenase at high rates upon illumination. The highest stability of nitrogenase in these resting cells was observed when suspensions were exposed to a diurnal pattern of illumination rather than continuous light. Although nitrogenase function and synthesis are closely coupled to photosynthetic activity, the biosyntheses of bacteriochorophyll and nitrogenase are independent of each other and are most probably subject to different regulatory mechanisms by light.

This article has been cited by other articles:

• Cantera, J. J. L., Kawasaki, H., Seki, T. (2004). The nitrogen-fixing gene (nifH) of Rhodopseudomonas palustris: a case of lateral gene transfer?. Microbiology 150: 2237-2246 [Abstract] [Full Text]  
• Vignais, P. M., Dimon, B., Zorin, N. A., Tomiyama, M., Colbeau, A. (2000). Characterization of the Hydrogen-Deuterium Exchange Activities of the Energy-Transducing HupSL Hydrogenase and H2-Signaling HupUV Hydrogenase in Rhodobacter capsulatus. J. Bacteriol. 182: 5997-6004 [Abstract] [Full Text]  
• Elsen, S., Dischert, W., Colbeau, A., Bauer, C. E. (2000). Expression of Uptake Hydrogenase and Molybdenum Nitrogenase in Rhodobacter capsulatus Is Coregulated by the RegB-RegA Two-Component Regulatory System. J. Bacteriol. 182: 2831-2837 [Abstract] [Full Text]  
• MADIGAN, M. T., WALL, J. D., GEST, H. (1979). Dark Anaerobic Dinitrogen Fixation by a Photosynthetic Microorganism. Science 204: 1429-1430 [Abstract]