Advertisement

Reactions and Physicochemical Properties of the Nitrogenase Mofe Proteins

  • Barry E. Smith

Abstract

The enzyme nitrogenase consists of two, oxygen-sensitive, metal-loproteins, the MoFe protein and the Fe protein, both of which are essential for activity. In addition to the two proteins, enzyme action requires MgATP, which is hydrolyzed to MgADP and Pi, a source of low potential electrons, usually sodium dithionite in vitro, and an anaerobic environment.1–3 In addition to N2, the enzyme will reduce a number of small triple-bonded molecules (Table 1) and, in their absence, will reduce protons to H2, a reaction which is never in practice completely suppressed by other substrates. Carbon monoxide inhibits the reduction of all substrates but the proton.

Keywords

Electron Paramagnetic Resonance Nitrogen Fixation Electron Paramagnetic Resonance Spectrum Klebsiella Pneumoniae Electron Paramagnetic Resonance Signal 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    R. R. Eady and B. E. Smith, Physicochemical Properties of Nitrogenase and its Components, in: “A Treatise on Dinitrogen Fixation,” Sections I and II, R. W. F. Hardy, F. Bottoraley and R. C. Burns, eds., Wiley, New York, p. 399 (1979).Google Scholar
  2. 2.
    D. J. Lowe, B. E. Smith and R. R. Eady, The Structure and Mechanism of Nitrogenase, in: “Recent Advances in Biological Nitrogen Fixation,” N. S. Subba Rao, ed., Oxford & IBH, New Delhi, p. 34 (1979).Google Scholar
  3. 3.
    L. E. Mortenson and R. N. F. Thorneley, Nitrogenase, Ann. Rev. Biochem. 48:387 (1979).PubMedCrossRefGoogle Scholar
  4. 4.
    B. E. Smith, D. J. Lowe and R. C. Bray, Nitrogenase of Klebsiella pneumoniae. Electron Paramagnetic Studies on the Catalytic Mechanism, Biochem. J. 130:641 (1972).PubMedGoogle Scholar
  5. 5.
    B. E. Smith, D. J. Lowe and R. C. Bray, Studies by Electron Paramagnetic Resonance on the Catalytic Mechanism of Nitrogenase of Klebsiella pneumoniae, Biochem. J. 135:331 (1973).PubMedGoogle Scholar
  6. 6.
    B. E. Smith and G. Lang, Mössbauer Spectroscopy of the Nitrogenase Proteins from Klebsiella pneumoniae. Structural Assignments and Mechanistic Conclusions, Biochem. J. 137:169 (1974).PubMedGoogle Scholar
  7. 7.
    R. R. Eady, D. J. Lowe and R. N. F. Thorneley, Nitrogenase of Klebsiella pneumoniae: A Pre-Steady State Burst of ATP Hydrolysis is Coupled to Electron Transfer Between the Component Proteins, FEBS Lett. 95:211 (1978).PubMedCrossRefGoogle Scholar
  8. 8.
    B. E. Smith, unpublished results.Google Scholar
  9. 9.
    H. Berndt, D. J. Lowe and M. G. Yates, The Nitrogen-Fixing System of Corynebacterium autotrophicum. Purification and Properties of the Nitrogenase Components and Two Ferredoxins, Eur. J. Biochem. 86:133 (1978).PubMedCrossRefGoogle Scholar
  10. 10.
    P. A. McLean and R. A. Dixon, Requirements for nifV Gene for Production of Wild-Type Nitrogenase Enzyme in Klebsiella pneumoniae, Nature (London) 292:655 (1981).CrossRefGoogle Scholar
  11. 11.
    P. T. Bui and L. E. Mortenson, The Role of Molybdoferredoxin in N2 Reduction: Its Reaction with ATP, Fed. Proc. 26:725 (1967).Google Scholar
  12. 12.
    D. R. Biggins and M. Kelly, Interaction of Nitrogenase from Klebsiella pneumoniae with ATP or Cyanide, Biochim. Biophys. Acta 205:288 (1970).PubMedCrossRefGoogle Scholar
  13. 13.
    R. W. F. Hardy and E. Knight, Jr., Biochemistry and Postulated Mechanisms of Nitrogen Fixation, in: “Progress in Phyto-chemistry,” L. Reinhold and L. Liwschitz, eds., Wiley-Interscience, London, Vol. 1, p. 407 (1968).Google Scholar
  14. 14.
    P. T. Bui and L. E. Mortenson, Mechanism of the Enzymic Reduction of N2: The Binding of Adenosine 5-Triphosphate and Cyanide to the N2-Reducing System, Proc. Nat. Acad. Sci. USA 61:1021 (1968).PubMedCrossRefGoogle Scholar
  15. 15.
    B. E. Smith, R. N. F. Thorneley, R. R. Eady and L. E. Mortenson, Nitrogenases from Klebsiella pneumoniae and Clostridium pasteurianum. Kinetic Investigations of Cross-Reactions as a Probe of the Enzyme Mechanism, Biöchem. J. 157:439 (1976).PubMedGoogle Scholar
  16. 16.
    R. Silverstein and W. A. Bulen, Kinetic Studies of the Nitrogenase-Catalyzed Hydrogen Evolution and Nitrogen Reduction Reactions, Biochemistry 9:3809 (1970).PubMedCrossRefGoogle Scholar
  17. 17.
    L. C. Davis, V. K. Shah and W. J. Brill, Nitrogenase VII. Effect of Component Ratio, ATP and H2 on the Distribution of Electrons to Alternative Substrates, Biochim. Biophys. Acta 403:67 (1975).PubMedGoogle Scholar
  18. 18.
    R. N. F. Thorneley and A. Cornish-Bowden, Kinetics of Nitrogenase of Klebsiella pneumoniae. Heterotropic Interactions between Magnesium-Adenosine 5’-Diphosphate and Magnesium-Adenosine 5’-Triphosphate, Biochem. J. 165:255 (1977).PubMedGoogle Scholar
  19. 19.
    R. R. Eady, C. Kennedy, B. E. Smith, R. N. F. Thorneley, M. G. Yates and J. R. Postgate, Nitrogenases in Azotobacter chroococcum and Klebsiella pneumoniae, Biochem. Soc. Trans. 3:488 (1975).PubMedGoogle Scholar
  20. 20.
    R. J. Rennie, A. Funnell and B. E. Smith, Immunochemistry of Nitrogenase as a Probe for the Enzyme Mechanism. Evidence for Multiple Enzyme Forms and an MgATP2- Binding Site on the Mo-Fe Protein, FEBS Lett. 91:158 (1978).PubMedCrossRefGoogle Scholar
  21. 21.
    R. W. Miller, R. L. Robson, M. G. Yates and R. R. Eady, Catalysis of Exchange of Terminal Phosphate Groups of ATP and ADP by Purified Nitrogenase Proteins, Can. J. Biochem. 58:542 (1980).PubMedCrossRefGoogle Scholar
  22. 22.
    C. Kennedy, R. R. Eady, A. Kondorosi and D. K. Rekosh, The Molybdenum-Iron Protein of Klebsiella pneumoniae Nitrogenase. Evidence for Non-Identical Subunits from Peptide ‘Mapping’, Biochem. J. 155:383 (1976).PubMedGoogle Scholar
  23. 23.
    R. Dixon, C. Kennedy, A. Kondorosi, V. Krishnapillai and M. Merrick, Complementation Analysis of Klebsiella pneumoniae Mutants Defective in Nitrogen Fixation, Molec. Gen. Genet. 157:189 (1977).PubMedCrossRefGoogle Scholar
  24. 24.
    T. C. Huang, W. G. Zumft and L. E. Mortenson, Structure of the Molybdoferredoxin Complex from Clostridium pasteurianum and Isolation of its Subunits, J. Bact. 113:884 (1973).PubMedGoogle Scholar
  25. 25.
    R. H. Swisher, M. L. Landt and R. J. Reithel, The Molecular Weight of, and Evidence for Two Types of Subunits in, the Molybdenum-Iron Protein of Azotobacter vinelandii Nitrogenase, Biochem. J. 163:427 (1977).PubMedGoogle Scholar
  26. 26.
    R. R. Eady, B. E. Smith, K. A. Cook and J. R. Postgate, Nitrogenase of Klebsiella pneumoniae. Purification and Properties of the Component Proteins, Biochem. J. 128:655 (1972).PubMedGoogle Scholar
  27. 27.
    M. G. Yates and K. Planqué, Nitrogenase from Azotobacter chroococcum. Purification and Properties of the Component Proteins, Eur. J. Biochem. 60:467 (1975).PubMedCrossRefGoogle Scholar
  28. 28.
    D. W. Israel, R. L. Howard, H. J. Evans and S. A. Russell, Purification and Characterization of the Molybdenum-Iron Protein Component of Nitrogenase from Soybean Nodule Bacteroids, J. Biol. Chem. 249:500 (1974).PubMedGoogle Scholar
  29. 29.
    M. J. Whiting and M. J. Dilworth, Legume Root Nodule Nitrogenase. Purification, Properties and Studies on its Genetic Control. Biochim. Biophys. Acta 371:337 (1976).Google Scholar
  30. 30.
    R. C. Burns, R. D. Holsten and R. W. F. Hardy, Isolation by Crystallization of the Mo-Fe Protein of Azotobacter nitrogenase, Biochem. Biophys. Res. Commun. 39:90 (1970).PubMedCrossRefGoogle Scholar
  31. 31.
    J. T. Stasny, R. C. Burns, B. D. Korant and R. W. F. Hardy, Electron Microscopy of the Mo-Fe Protein from Azotobacter Nitrogenase, J. Cell Biol. 60:311 (1974).PubMedCrossRefGoogle Scholar
  32. 32.
    D. Kleiner and C. H. Chen, Physical and Chemical Properties of the Nitrogenase Proteins from Azotobacter vinelandii, Arch. Microbiol. 98:93 (1974).CrossRefGoogle Scholar
  33. 33.
    W. A. Bulen, Nitrogenase from Azotobacter vinelandii and Reactions Affecting Mechanistic Interpretations, in: “Proc. First Internat. Symp. Nitrogen Fixation,” W. E. Newton and C. J. Nyman, eds., Washington State University Press, Pullman, Washington, U. S. A., Vol. 1, p. 177 (1976).Google Scholar
  34. 34.
    T. C. Huang, W. G. Zumft and L. E. Mortenson, Structure of the Molybdoferredoxin Complex from Clostridium pasteurianum and Isolation of its Subunits, J. Bact. 113:884 (1973).PubMedGoogle Scholar
  35. 35.
    H. Dalton, J. A. Morris, M. A. Ward and L. E. Mortenson, Purification and Some Properties of Molybdoferredoxin, a Component of Nitrogenase from Clostridium pasteurianum, Biochemistry 10:2066 (1971).PubMedCrossRefGoogle Scholar
  36. 36.
    J. S. Chen, J. S. Multani and L. E. Mortenson, Structural Investigation of Nitrogenase Components from Clostridium pasteurianum and Comparison with Similar Components of Other Organisms, Biochim. Biophys. Acta 310:51 (1973).PubMedGoogle Scholar
  37. 37.
    M. Y. W. Tso, Some Properties of the Nitrogenase Proteins from Clostridium pasteurianum. Molecular Weight, Subunit Structure, Isoelectric Point and EPR Spectra, Arch. Microbiol. 99:71 (1974).PubMedCrossRefGoogle Scholar
  38. 38.
    J. Meyer and G. Zaccai, Neutron Small Angle Scattering of the Mo-Fe Protein from Clostridium pasteurianum, in: “Current Perspectives in Nitrogen Fixation,” A. H. Gibson and W. E. Newton, eds., Australian Academy of Science, Canberra, p. 359 (1981).Google Scholar
  39. 39.
    M. Matsubara, T. Hase, T. Nakano and W. G. Zumft, Sequence Determination of MoFe-Protein of Clostridial Nitrogenase, in: “Current Perspectives in Nitrogen Fixation,” A. H. Gibson and W. E. Newton, eds., Australian Academy of Science, Canberra, p. 362 (1981).Google Scholar
  40. 40.
    W. G. Zumft, T. Hase and M. Matsubara, Studies on the Subunits of Clostridial Molybdenum-Iron Protein, in: “Molybdenum Chemistry of Biological Significance,” W. E. Newton and S. Otsuka, eds., Plenum, New York, p. 59 (1980).CrossRefGoogle Scholar
  41. 41.
    D. J. Lundell and J. B. Howard, Isolation and Partial Characterization of Two Different Subunits from the Molybdenum-Iron Protein of Azotobacter vinélandii Nitrogenase, J. Biol. Chem. 253:3422 (1978).PubMedGoogle Scholar
  42. 42.
    B. E. Smith, R. N. F. Thorneley, M. G. Yates, R. R. Eady and J. R. Postgate, Structure and Function of Nitrogenase from Klebsiella pneumoniae and Azotobacter chroococcum, in: “Proc. First Internat. Symp. Nitrogen Fixation,” W. E. Newton and C. J. Nyman, eds., Washington State University Press, Pullman, Washington, U.S.A., Vol. 1, p. 150 (1976).Google Scholar
  43. 43.
    D. M. Kurtz, Jr., R. S. McMillan, B. K. Burgess, L. E. Mortenson and R. H. Holm, Identification of Iron-Sulfur Centers in the Iron-Molybdenum Proteins of Nitrogenase, Proc. Nat. Acad. Sci. USA 76:4986 (1979).PubMedCrossRefGoogle Scholar
  44. 44.
    P. E. Bishop, D. M. L. Jarlenski and D. R. Hetherington, Evidence for an Alternative Nitrogen Fixation System in Azotobacter vinelandii, Proc. Natl. Acad. Sci. USA 77:7342 (1980).PubMedCrossRefGoogle Scholar
  45. 45.
    V. K. Shah and W. J. Brill, Isolation of an Iron-Molybdenum Cofactor from Nitrogenase, Proc. Natl. Acad. Sci. USA 74:3249 (1977).PubMedCrossRefGoogle Scholar
  46. 46.
    G. B. Wong, D. M. Kurtz, Jr., R. H. Holm, L. E. Mortenson and R. G. Upchurch, A 19F NMR Method for Identification of Iron-Sulfur Cores Extruded from Active Centers of Proteins, with Applications to Milk Xanthine Oxidase and the Iron-Molybdenum Proteins of Nitrogenase, J. Am. Chem. Soc. 101:3078 (1979).CrossRefGoogle Scholar
  47. 47.
    B. A. Averill, J. R. Bale and W. H. Orme-Johnson, Displacement of Iron-Sulfur Clusters from Ferredoxins and Other Iron-Sulfur Proteins, J. Am. Chem. Soc. 100:3034 (1978).CrossRefGoogle Scholar
  48. 48.
    B. K. Burgess, D. B. Jacobs and E. I. Stiefel, Large-Scale Purification of High Activity Azotobacter vinélandii Nitrogenase, Biochim. Biophys. Acta 614:196 (1980).PubMedGoogle Scholar
  49. 49.
    S. P. Cramer, W. O. Gillum, K. O. Hodgson, L. E. Mortenson, E. I. Stiefel, J. R. Chisnell, W. J. Brill and V. K. Shah, The Molybdenum Site of Nitrogenase. 2. A Comparative Study of Mo-Fe Proteins and the Iron-Molybdenum Cofactor by X-Ray Absorption Spectroscopy, J. Am. Chem. Soc. 100:3814 (1975).CrossRefGoogle Scholar
  50. 50.
    B.- K. Teo and B. A. Averill, A New Cluster Model for the FeMo-Cofactor of Nitrogenase, Biochem. Biophys. Res. Commun. 88:1454 (1979).CrossRefGoogle Scholar
  51. 51.
    W. E. Newton, J. W. McDonald, G. D. Friesen, B. K. Burgess, S. D. Conradson and K. O. Hodgson, Molybenum-Iron-Sulfur Complexes and Their Relevance to the Molybdenum Site of Nitrogenase, in: “Current Perspectives in Nitrogen Fixation,” A. H. Gibson and W. E. Newton, eds., Australian Academy of Science, Canberra, p. 30 (1981).Google Scholar
  52. 52.
    T. E. Wolff, J. M. Berg, K. O. Hodgson, R. B. Frankel and R. H. Holm, Synthetic Approaches to the Molybdenum Site in Nitrogenase. Preparation and Structural Properties of the Molybdenum-Iron-Sulfur ‘Double Cubane’ Cluster Complexes [Mo2Fe6S8(SC2H5)9]3- and [Mo2Fe6S9(SC2H5)8]3-, J. Am. Chem. Soc. 101:4140 (1979).CrossRefGoogle Scholar
  53. 53.
    W. G. Zumft, W. C. Cretney, T. C. Huang, L. E. Mortenson and G. Palmer, On the Structure and Function of Nitrogenase from Clostridium pasteurianum W5, Biochem. Biophys. Res. Commun. 48:1525 (1972).PubMedCrossRefGoogle Scholar
  54. 54.
    M. C. W. Evans, A. Telder and R. V. Smith, The Purification and Some Properties of the Molybdenum-Iron Protein of Chromatium Nitrogenase, Biochim. Biophys. Acta 310:344 (1973).Google Scholar
  55. 55.
    L. C. Davis, V. K. Shah, W. J. Brill and W. H. Orme-Johnson, Nitrogenase II. Changes in the EPR Signal of Component I (Iron-Molybdenum Protein) of Azotobacter vinelandii Nitrogenase during Repression and Derepression, Biochim. Biophys, Acta 256:512 (1972).CrossRefGoogle Scholar
  56. 56.
    W. H. Orme-Johnson, W. D. Hamilton, T. Ljones, M. Y. W. Tso, R. H. Burris, V. K. Shah and W. J. Brill, Electron Paramagnetic Resonance of Nitrogenase and Nitrogenase Components from Clostridium pasteurianum W5 and Azotobacter vinelandii OP, Proc. Natl. Acad. Sci. USA 69:3142 (1972).PubMedCrossRefGoogle Scholar
  57. 57.
    G. Palmer, J. S. Multani, W. C. Cretney, W. G. Zumft and L. E. Mortenson, Electron Paramagnetic Resonance Studies on Nitrogenase I. The Properties of Molybdoferredoxin and Azoferredoxin, Arch. Biochem. Biophys. 153:325 (1972).PubMedCrossRefGoogle Scholar
  58. 58.
    J. Rawlings, V. K. Shah, J. R. Chisnell, W. J. Brill, R. Zimmerman, E. Münck and W. H. Orme-Johnson, Novel Metal Cluster in the Iron-Molybdenum Cofactor of Nitrogenase, J. Biol. Chem. 253:1001 (1978).PubMedGoogle Scholar
  59. 59.
    E. Münck, H. Rhodes, W. H. Orme-Johnson, L. C. Davis, W. J. Brill and V. K. Shah, Nitrogenase VIII. Mössbauer and EPR Spectroscopy. The MoFe Protein Component from Azotobacter vinelandii, Biochim. Biophys. Acta 400:32 (1975).PubMedGoogle Scholar
  60. 60.
    B. E. Smith, Studies on the Iron-Molybdenum Cofactor from the Nitrogenase Mo-Fe Protein of Klebsiella pneumoniae, in: “Molybdenum Chemistry of Biological Significance,” W. E. Newton and S. Otsuka, eds., Plenum, New York, p. 179 (1980).CrossRefGoogle Scholar
  61. 61.
    W. G. Zumft and L. E. Mortenson, Evidence for a Catalytic Center Heterogeneity of Molybdoferredoxin from Clostridium pasteurianum, Eur. J. Biochem. 35:401 (1973).PubMedCrossRefGoogle Scholar
  62. 62.
    T. R. Hawkes, Purification and Properties of the MoFe Protein from nifB Mutants of Klebsiella pneumoniae, D. Phil. Thesis, university of Sussex (1981).Google Scholar
  63. 63.
    M. J. O’Donnell, Structure and Function of the MoFe Protein of Nitrogenase, D. Phil. Thesis, University of Sussex (1978).Google Scholar
  64. 64.
    R. W. F. Hardy, R. C. Burns, R. R. Herbert, R. D. Holsten and E. K. Jackson, Biological Nitrogen Fixation: A Key to World Protein, Plant Soil, Special Volume:561 (1971).Google Scholar
  65. 65.
    R. N. F. Thorneley, J. Chatt, R. R. Eady, D. J. Lowe, M. J. O’Donnell, J. R. Postgate, R. L. Richards and B. E. Smith, The Mechanisms of Biological Nitrogen Fixation: Transient Complexes in Catalytic Cycles, in: “Nitrogen Fixation,” W. E. Newton and W. H. Orme-Johnson, eds., University Park Press, Baltimore, Vol. 1, p. 171 (1980).Google Scholar
  66. 66.
    W. H. Orme-Johnson, P. Lindahl, J. Meade, W. Warren, M. Nelson, S. Groh, N. R. Orme-Johnson, E. Münck, B. H. Huynh, M. Emptage, J. Rawlings, J. Smith, J. Roberts, B. Hoffmann and W. B. Mims, Nitrogenase: Prosthetic Groups and Their Reactivities, in: “Current Perspectives in Nitrogen Fixation,” A. H. Gibson and W. E. Newton, eds., Australian Academy of Science, Canberra, p. 79 (1981).Google Scholar
  67. 67.
    D. J. Lowe, R. R. Eady and R. N. F. Thorneley, Electron Paramagnetic Resonance Studies on Nitrogenase of Klebsiella pneumoniae. Evidence for Acetylene- and Ethylene-Nitrogenase Transient Complexes, Biochem. J. 173:277 (1978).PubMedGoogle Scholar
  68. 68.
    L. C. Davis, M. T. Henzl, R. H. Burris and W. H. Orme-Johnson, Iron-Sulfur Clusters in the Molybdenum-Iron Protein Component of Nitrogenase. Electron Paramagnetic Resonance of the Carbon Monoxide Inhibited State, Biochemistry 18:4860 (1979).PubMedCrossRefGoogle Scholar
  69. 69.
    M. G. Yates and D. J. Lowe, Nitrogenase of Azotobacter chroococcum: A New Electron-Paramagnetic-Resonance Signal Associated with a Transient Species of the MoFe-Protein During Catalysis, FEBS Lett. 72:121 (1976).PubMedCrossRefGoogle Scholar
  70. 70.
    D. J. Lowe, R. M. Lynden-Bell and R. C. Bray, Spin-Spin Interaction Between Molybdenum and one of the Iron-Sulfur Systems of Xanthine Oxidase and its Relevance to the Enzymic Mechanism, Biöchem. J. 130:239 (1972).PubMedGoogle Scholar
  71. 71.
    W. H. Orme-Johnson, N. R. Orme-Johnson, C. Touton, M. Emptage, M. Henzl, J. Rawlings, K. Jacobson, J. P. Smith, W. B. Mims, B. H. Huynh, E. Münck and G. S. Jacob, Spectroscopic and Chemical Evidence for the Nature and Role of Metal Centers in Nitrogenase and Nitrate Reductase, in: “Molybdenum Chemistry of Biological Significance,” W. E. Newton and S. Otsuka, eds., Plenum Press, New York, p. 85 (1980).CrossRefGoogle Scholar
  72. 72.
    B. E. Smith, M. J. O’Donnell, G. Lang, K. Spartalian, A Mössbauer Spectroscopic Investigation of the Redox Behavior of the Molybdenum-Iron Protein from Klebsiella pneumoniae Nitrogenase, Biochem. J. 191:449 (1980).PubMedGoogle Scholar
  73. 73.
    R. Zimmermann, E. Münck, W. J. Brill, V. K. Shah, M. T. Henzl, J. Rawlings and W. H. Orme-Johnson, Nitrogenase X: Mössbauer and EPR Studies on Reversibly Oxidized MoFe Protein from Azotobacter vinelandii Nature of the Iron Centers, Biochim. Biophys. Acta 537:185 (1978).PubMedGoogle Scholar
  74. 74.
    B. H. Huynh, E. Münck and W. H. Orme-Johnson, Nitrogenase XI. Mössbauer Studies on the Cofactor Centers of the MoFe Protein from Azotobacter vinelandii, Biochim, Biophys. Acta 527:192 (1979).Google Scholar
  75. 75.
    B. H. Huynh, M. T. Henzl, J. A. Christner, R. Zimmerman, W. H. Orme-Johnson and E. Münck, Nitrogenase XII. Mössbauer Studies of the MoFe Protein from Clostridium pasteurianum, Biochim. Biophys. Acta 623:124 (1980).PubMedGoogle Scholar
  76. 76.
    V. K. Shah and W. J. Brill, Nitrogenase IV. Simple Method of Purification to Homogeneity of Nitrogenase Components from Azotobacter vinelandii, Biochim. Biophys. Acta 305:445 (1973).PubMedCrossRefGoogle Scholar
  77. 77.
    W. A. Bulen and J. R. LeComte, The Nitrogenase System from Azotobacter: Two Enzyme Requirements for N2 Reduction, ATP Dependent H2 Evolution and ATP Hydrolysis, Proc. Natl. Acad. Sci. USA 56:979 (1966).PubMedCrossRefGoogle Scholar
  78. 78.
    P. J. Stephens, C. E. McKenna, B. E. Smith, H. T. Nguyen, M. C. McKenna, A. J. Thomson, F. Devlin and J. B. Jones, Circular Dichroism and Magnetic Circular Dichroism of Nitrogenase Proteins, Proc. Natl. Acad. Sci. USA 76:2585 (1979).PubMedCrossRefGoogle Scholar
  79. 79.
    R. V. Klucas, B. Koch, S. A. Russell and H. J. Evans, Purification and Some Properties of the Nitrogenase from Sobyean (Glycine max Merr.) Nodules, Plant Physiol. 43:1906 (1968).PubMedCrossRefGoogle Scholar
  80. 80.
    D. Y. Jeng, J. A. Morris and L. E. Mortenson, The Effect of Reductant in Inorganic Phosphate Release from Adenosine 5’-Triphosphate by Purified Nitrogenase of Clostridium pasteurianum, J. Biol. Chem. 245:2809 (1970).PubMedGoogle Scholar
  81. 81.
    G. A. Walker and L. E. Mortenson, An Effect of Magnesium Adenosine 5-Triphosphate on the Structure of Azoferredoxin from Clostridium pasteurianum, Biochem. Biophys. Res. Commun. 53:904 (1973).PubMedCrossRefGoogle Scholar
  82. 82.
    V. K. Shah and W. J. Brill, Nitrogenase IV: Simple Method of Purification to Homogeneity of Nitrogenase Components from Azotobacter vinelandii, Biochim. Biophys. Acta 305:445 (1973).PubMedCrossRefGoogle Scholar
  83. 83.
    P. J. Stephens, C. E. McKenna, M. C. McKenna, H. T. Nguyen, T. V. Morgan and F. Devlin, Circular Dichroism and Magnetic Circular Dichroism of Nitrogenase Proteins, in: “Current Perspectives in Nitrogen Fixation,” A. H. Gibson and W. E. Newton, eds., Australian Academy of Science, Canberra, p. 357 (1981).Google Scholar
  84. 84.
    P. J. Stephens, A. J. Thomson, T. A. Keiderling, J. Rawlings, K. K. Rao and D. O. Hall, Cluster Characterization in Iron-Sulfur Proteins by Magnetic Circular Dichroism, Proc. Natl. Acad. Sci. USA 75:5273 (1978).PubMedCrossRefGoogle Scholar
  85. 85.
    P. J. Stephens, A. J. Thomson, J. B. R. Dunn, T. A. Keiderling, J. Rawlings, K. K. Rao and D. O. Hall, Circular Dichroism and Magnetic Circular Dichroism of Iron-Sulfur Proteins, Biochemistry 17:4770 (1978).PubMedCrossRefGoogle Scholar
  86. 86.
    P. N. Schatz and A. J. McCaffery, The Faraday Effect, Quart. Rev. Chem. Soc. 4:552 (1969).CrossRefGoogle Scholar
  87. 87.
    A. J. Thomson and M. K. Johnson, Magnetization Curves of Haemoproteins Measured by Low-Temperature Magnetic Circular Dichroism Spectroscopy, Biochem. J. 191:411 (1980).PubMedGoogle Scholar
  88. 88.
    M. J. Johnson, A. J. Thomson, A. E. Robinson and B. E. Smith, Characterization of the Paramagnetic Centers of the Molybdenum-Iron Protein of Nitrogenase from Klebsiella pneumoniae Using Low Temperature Magnetic Circular Dichroism Spectroscopy, Biochim. Biophys. Acta, submitted.Google Scholar
  89. 89.
    G. D. Watt, An Electrochemical Method of Measuring Redox Potentials of Low Potential Proteins by Microcoulometry at Controlled Potentials, Anal. Biochem. 99:399 (1979).PubMedCrossRefGoogle Scholar
  90. 90.
    M. J. O’Donnell and B. E. Smith, Electron-Parmagnetic-Resonance Studies on the Redox Properties of the Molybdenum-Iron Protein of Nitrogenase Between +50 and -450 mV, Biochem. J. 173:831 (1978).PubMedGoogle Scholar
  91. 91.
    W. G. Zumft, L. E. Mortenson and G. Palmer, Electron Paramagnetic Resonance Studies on Nitrogenase. Investigation of the Oxidation-Reduction Behavior of Azoferredoxin and Molybdoferredoxin with Potentiometric and Rapid-Freeze Techniques, Eur. J. Biochem. 46:525 (1974).PubMedCrossRefGoogle Scholar
  92. 92.
    S. L. Albrecht and M. C. W. Evans, Measurement of the Oxidation Reduction Potential of the EPR Detectable Active Center of the Molybdenum Iron Protein of Chromatium Nitrogenase, Biochem. Biophys. Res. Commun. 55:1009 (1973).PubMedCrossRefGoogle Scholar
  93. 93.
    G. D. Watt, A. Burns, S. Lough and D. L. Tennent, Redox and Spectroscopic Properties of Oxidized MoFe Protein from Azotobacter vinelandii, Biochemistry 19:4926 (1980).PubMedCrossRefGoogle Scholar
  94. 94.
    G. D. Watt, Redox Titrations of the FeMo Protein of Nitrogenase, in: “Current Perspectives in Nitrogen Fixation,” A. H. Gibson and W. E. Newton, eds., Australian Academy of Science, Canberra, p. 52 (1981).Google Scholar
  95. 95.
    B. E. Smith, The Structure and Function of Nitrogenase: A Review of the Evidence for the Role of Molybdenum, J. Less-Common Metals 54:465 (1977).CrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1983

Authors and Affiliations

  • Barry E. Smith
    • 1
  1. 1.ARC Unit of Nitrogen FixationUniversity of SussexBrighton, SussexUK

Personalised recommendations