Protein synthesis and protein phosphorylation in Bradyrhizobium japonicum bacteroids
Biological nitrogen fixation requires a large portion of an organisms energy metabolism. Free-living diazotrophs fixing atmospheric nitrogen have longer doubling times than cultures supplied fixed nitrogen compounds. During symbiotic nitrogen fixation, the microsymbiont does not grow significantly during the most active phase of dinitrogen reduction. The non-growing condition of the microsymbionts could provide the necessary energy for nitrogen fixation. As much as 80% of the metabolic energy of a cell may be used for protein synthesis (6). The switching of metabolic energy from protein synthesis to dinitrogen reduction could supply the energy needs of nitrogen fixation without requiring additional energy sources or invoking supplemental metabolic pathways. This concept of switching energy from protein synthesis to dinitrogen fixation was first proposed by Perry Wilson in his studies on metabolism in non-growing cultures (12).
KeywordsNitrogen Fixation Symbiotic Nitrogen Fixation Acetylene Reduction Activity Young Nodule Additional Energy Source
Unable to display preview. Download preview PDF.
- 2.Bisseling, T., van den Bos, R.C., Weststrate, M.W., Hakkaart, M.J J. & van Kammen, A. (1979) Biochim. Biophys. Acta 562, 515–526.Google Scholar
- 4.Karr, D.B. & Emerich, D.W. (1989) J. Bacteriol. 171, 3420–3426.Google Scholar
- 5.Krishnan, H. & Pueppke, S.G. (1989) Symbiosis 7, 127–138.Google Scholar
- 6.Lehninger, A. (1965) Bioenergetics (W.A. Benjamin, Inc., New York).Google Scholar
- 7.McRae, D.G., Miller, R.W. & Berndt, W.B. (1989) Symbiosis 7, 67–80.Google Scholar
- 8.Reibach, P.H. & Streeter, J.G. (1984) J. Bacteriol. 159, 47–52.Google Scholar
- 9.Shaw, B.D. & Sutton, W.D. (1979) Biochim. Biophys. Acta 563, 216–226.Google Scholar
- 11.van den Bos, R.C., Bisseling, T. & van Kammen (1978) J. Gen Microbiol. 109, 131–139.Google Scholar
- 12.Wilson, P.W. (1938) J. Bacteriol. 35, 601–623.Google Scholar