Nitrogen Fixation in Klebsiella pneumoniae: Nitrogenase Levels and the Effect of Added Molybdate on Nitrogenase Derepressed under Molybdenum Deprivation
Klebsiella pneumoniae had low levels of nitrogenase activity and antigenic cross reacting material to both nitrogenase components when grown, or when the nif operons were derepressed, under Mo-deficient conditions. When molybdate (100 μm) was added to Mo-deprived cultures shortly after initiating derepression of nitrogenase, activity was rapidly restored and reached up to 60% of that of control cultures supplied with molybdate throughout derepression. Restoration of activity was prevented by chloramphenicol (200 μg ml −1) but not by tetracycline (100 μg ml −1), although both compounds inhibited general protein synthesis at these concentrations. Expression of the nif structural genes was not rapidly stimulated by added molybdate, so the rapid stimulation of activity was due to the activation of a low level of apoprotein present in Mo-deprived cultures. After 16 h of Mo-deprivation, suspensions no longer responded rapidly to added molybdate, consistent with the finding that, when further protein synthesis was inhibited by the addition of chloramphenicol after 4 h Mo-deprivation, polypeptides of the MoFe protein (Kp1) but not the Fe protein (Kp2) of nitrogenase were degraded within the following 18 h.
AndersenK., ShanmugamK. T., ValentineR. C.1977; Nitrogen fixation {nif) regulatory mutants of Klebsiella-, determination of the energy cost of nitrogen fixation in vivo. In Genetic Engineering for Nitrogen Fixation pp. 95–110HolleanderA. Edited by New York: Plenum Press.;
BrillW. J., SteinerA. L., ShahV. K.1974; Effect of molybdenum starvation and tungsten on the synthesis of nitrogenase components in Klebsiella pneumoniae. Journal of Bacteriology 118:986–989
CannonF. C., DixonR. A., PostgateJ. R., PrimroseS. B.1974; Chromosomal integration of nitrogen fixation genes in Escherichia coli. Journal of General Microbiology 80:227–239
EadyR. R., SmithB. E.1979; Physicochemical properties of nitrogenase and its components. In A Treatise on Dinitrogen Fixation sec. 1 & 2 pp. 399–490HardyR. W. F., BottomleyF., BurnsR. C. Edited by New York: Wiley;
EadyR. R., SmithB. E., CookK. A., PostgateJ. R.1972; Nitrogenase of Klebsiella pneumoniae:purification and properties of the component proteins. Biochemical Journal 128:655–675
EadyR. R., IssackR., KennedyC., PostgateJ. R., RatcliffeH. D.1978; Nitrogenase synthesis in Klebsiella pneumoniae: comparison of ammonium and oxygen regulation. Journal of General Microbiology 104:277–285
HallenbeckP. C., BenemannJ. R.1980; Effect of molybdenum starvation and tungsten on the synthesis and activity of nitrogenase in Anabaena cylindrica. In Nitrogen Fixation {Enzymology, Physiology, Genetics): Applications in H2 and NH3 Production. Abstracts of a Société de Chimie Biologique/Commission of the European Community meeting on Nitrogen Fixation, Grenoble June1980VignaisP. M.
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KennedyC., PostgateJ. R.1977; Expression of Klebsiella pneumoniae nitrogen fixation genes in nitrate reductase mutants of Escherichia coli. Journal of General Microbiology 98:551–557
KennedyC., EadyR. R., KondorosiE., RekoshD.1976; The molybdenum-iron protein of Klebsiella pneumoniae nitrogenase. Evidence for non-identical subunits from peptide mapping. Biochemical Journal 155:383–389
KleinerD., PhillipsS.1981; Relative levels of guanosine-3ʹ -diphosphate-5ʹ -diphosphate (ppGpp) in some N2-fixing bacteria during derepression and repression of nitrogenase. Archives of Microbiology 128:341–342
NagataniH. H., BrillW. J.1974; The effect of Mo, W and V on the synthesis of nitrogenase components in Azotobacter vinelandii. Biochimica et biophysica acta 362:160–166
NagataniH. H., HaselkornR.1978; Molybdenum independence of nitrogenase component synthesis in the non-heterocystous cyanobacterium Plectonema. Journal of Bacteriology 134:597–605
PostgateJ. R., EadyR. R., DixonR. A., HillS., KahnD., KennedyC., PartridgeP., RobsonR., YatesM. G.1981; Some aspects of the physiology of dinitrogen fixation. In Biological Metabolism of Inorganic Nitrogen and Sulphur Compounds pp. 103–115BotheH., TrebstA. Edited by Berlin, Heidelberg & New York: Springer;
RennieR. J., FunnellA., SmithB. E.1978; Immunochemistry of nitrogenase as a probe for the enzyme mechanism. Evidence for multiple enzyme forms and an Mg ATP2- binding site on the MoFe protein. FEBS Letters 91:158–161
RobertsG. P., MacneilT., MacneilD., BrillW. J.1978; Regulation and characterisation of protein products encoded by the nif (nitrogen fixation) genes of Klebsiella pneumoniae. Journal of Bacteriology 136:267–279
Nitrogen Fixation in Klebsiella pneumoniae: Nitrogenase Levels and the Effect of Added Molybdate on Nitrogenase Derepressed under Molybdenum Deprivation