Publications

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121. Danyal, K., Rasmussen, A. J., Keable, S. M., Inglet, B. S., Shaw, S., Zadvornyy, O. A., Duval, S., Dean, D. R., Raugei, S., Peters, J. W., and Seefeldt, L. C. (2015) Fe protein-independent substrate reduction by nitrogenase MoFe protein variants. Biochemistry 54, 2456–2462. doi: 10.1021/acs.biochem.5b00140

120. Lukoyanov, D., Yang, Z.-Y., Khadka, N., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2015) Identification of a key catalytic intermediate demonstrates that nitrogenase is activated by the reversible exchange of N2 for H2. J. Am. Chem. Soc. 137, 3610–3615. doi: 10.1021/jacs.5b00103

119. McCurdy, A. T., Higham, A. J., Morgan, M. R., Quinn, J. C., and Seefeldt, L. C. (2015) Two-step process for production of biodiesel blends from oleaginous yeast and microalgae. Fuel 137, 269–276. doi: 10.1016/j.fuel.2014.07.099

118. Willis, R. M., McCurdy, A. T., Ogborn, M. K., Wahlen, B. D., Quinn, J. C., Pease III, L. F., and Seefeldt, L. C. (2014) Improving energetics of triacylglyceride extraction from wet oleaginous microbes. Bioresource Technology 167, 416–424. doi: 10.1016/j.biortech.2014.06.013

117. Shaw, S., Lukoyanov, D., Danyal, K., Dean, D. R., Hoffman, B. M., and Seefeldt, L. C. (2014) Nitrite and hydroxylamine as nitrogenase substrates: mechanistic implications for the pathway of N2 reduction. J. Am. Chem. Soc. 136, 12776–12783. doi: 10.1021/ja507123d

116. Willis, R. M., McCurdy, A. T., Ogborn, M. K., Wahlen, B. D., Quinn, J. C., Pease III, L. F., and Seefeldt, L. C. (2014) Improving energetics of triacylglyceride extraction from wet oleaginous microbes. Bioresource Technology 167, 416–424. doi: 10.1016/j.biortech.2014.06.013

115. Smith, D., Danyal, K., Raugei, S., and Seefeldt, L. C. (2014) Substrate channel in nitrogenase revealed by a molecular dynamics approach. Biochemistry53, 2278–2285. doi: 10.1021/bi401313j

114. Lukoyanov, D., Yang, Z.-Y., Duval, S., Danyal, K., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2014) A confirmation of the quench-cryoannealing relaxation protocol for identifying reduction states of freeze-trapped nitrogenase intermediates. Inorg. Chem. 53, 3688–3693. doi: 10.1021/ic500013c

113. Hoffman, B. M., Lukoyanov, D., Yang, Z.-Y., Dean, D. R., and Seefeldt, L. C. (2014) Mechanism of nitrogen fixation by nitrogenase: the next stage. Chem. Rev. 114, 4041–4062. doi: 10.1021/cr400641x

112. Yang, Z.-Y., Khadka, N., Lukoyanov, D., Hoffman, B. M., Dean, D. R., and Seefeldt, L. C. (2013) On reversible H2 loss upon N2 binding to FeMo-cofactor of nitrogenase. Proc. Natl. Acad. Sci. U.S.A 110, 16327–16332.

111. Wahlen, B. D., Morgan, M. R., McCurdy, A. T., Willis, R. M., Morgan, M. D., Dye, D. J., Bugbee, B., Wood, B. D., and Seefeldt, L. C. (2013) Biodiesel from microalgae, yeast, and bacteria: engine performance and exhaust emissions. Energy Fuels 27, 220–228.

110. Seefeldt, L. C., Yang, Z.-Y., Duval, S., and Dean, D. R. (2013) Nitrogenase reduction of carbon-containing compounds. Biochim. Biophys. Acta 1827, 1102–1111.

109. Moure, V. R., Danyal, K., Yang, Z.-Y., Wendroth, S., Müller-Santos, M., Pedrosa, F. O., Scarduelli, M., Gerhardt, E. C. M., Huergo, L. F., Souza, E. M., and Seefeldt, L. C. (2013) The nitrogenase regulatory enzyme dinitrogenase reductase ADP-ribosyltransferase (DraT) is activated by direct interaction with the signal transduction protein GlnB. J. Bacteriol. 195, 279–286.

108. Hoffman, B. M., Lukoyanov, D., Dean, D. R., and Seefeldt, L. C. (2013) Nitrogenase: a draft mechanism. Acc. Chem. Res. 46, 587–595.

107. Duval, S., Danyal, K., Shaw, S., Lytle, A. K., Dean, D. R., Hoffman, B. M., Antony, E., and Seefeldt, L. C. (2013) Electron transfer precedes ATP hydrolysis during nitrogenase catalysis. Proc. Natl. Acad. Sci. U.S.A 110, 16414–16419.

106. Appel, A. M., Bercaw, J. E., Bocarsly, A. B., Dobbek, H., DuBois, D. L., Dupuis, M., Ferry, J. G., Fujita, E., Hille, R., Kenis, P. J. A., Kerfeld, C. A., Morris, R. H., Peden, C. H. F., Portis, A. R., Ragsdale, S. W., Rauchfuss, T. B., Reek, J. N. H., Seefeldt, L. C., Thauer, R. K., and Waldrop, G. L. (2013) Frontiers, opportunities, and challenges in biochemical and chemical catalysis of CO2 fixation. Chem. Rev. 113, 6621–6658.

105. Adams, C., Godfrey, V., Wahlen, B., Seefeldt, L., and Bugbee, B. (2013) Understanding precision nitrogen stress to optimize the growth and lipid content tradeoff in oleaginous green microalgae. Bioresour. Technol. 131, 188–194.

104. Yang, Z.-Y., Moure, V. R., Dean, D. R., and Seefeldt, L. C. (2012) Carbon dioxide reduction to methane and coupling with acetylene to form propylene catalyzed by remodeled nitrogenase. Proc. Natl. Acad. Sci. U.S.A. 109, 19644–19648.

103. Seefeldt, L. C., Hoffman, B. M., and Dean, D. R. (2012) Electron transfer in nitrogenase catalysis. Curr. Opin. Chem. Biol. 16, 19–25.

102. Mayweather, D., Danyal, K., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2012) Temperature invariance of the nitrogenase electron transfer mechanism. Biochemistry 51, 8391–8398.

101. Lukoyanov, D., Yang, Z.-Y., Barney, B. M., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2012) Unification of reaction pathway and kinetic scheme for N2 reduction catalyzed by nitrogenase. Proc. Natl. Acad. Sci. U.S.A. 109, 5583–5587.

100. George, S. J., Barney, B. M., Mitra, D., Igarashi, R. Y., Guo, Y., Dean, D. R., Cramer, S. P., and Seefeldt, L. C. (2012) EXAFS and NRVS reveal a conformational distortion of the FeMo-cofactor in the MoFe nitrogenase propargyl alcohol complex. J. Inorg. Biochem. 112, 85–92.

99. Barney, B. M., Wahlen, B. D., Garner, E., Wei, J., and Seefeldt, L. C. (2012) Differences in substrate specificities of five bacterial wax ester synthases. Appl. Environ. Microbiol. 78, 5734–5745.

98. Yang, Z.-Y., Seefeldt, L. C., Dean, D. R., Cramer, S. P., and George, S. J. (2011) Steric control of the Hi-CO MoFe nitrogenase complex revealed by stopped-flow infrared spectroscopy. Angew. Chem. Int. Ed. Engl 50, 272–275.

97. Yang, Z.-Y., Dean, D. R., and Seefeldt, L. C. (2011) Molybdenum nitrogenase catalyzes the reduction and coupling of CO to form hydrocarbons. J. Biol. Chem. 286, 19417–19421.

96. Yang, Z.-Y., Danyal, K., and Seefeldt, L. C. (2011) Mechanism of Mo-dependent nitrogenase. Methods Mol. Biol. 766, 9–29.

95. Willis, R. M., Wahlen, B. D., Seefeldt, L. C., and Barney, B. M. (2011) Characterization of a fatty acyl-CoA reductase from Marinobacter aquaeolei VT8: a bacterial enzyme catalyzing the reduction of fatty acyl-CoA to fatty alcohol. Biochemistry 50, 10550–10558.

94. Wahlen, B. D., Willis, R. M., and Seefeldt, L. C. (2011) Biodiesel production by simultaneous extraction and conversion of total lipids from microalgae, cyanobacteria, and wild mixed-cultures. Biores. Technol. 102, 2724–2730.

93. Lukoyanov, D., Dikanov, S. A., Yang, Z.-Y., Barney, B. M., Samoilova, R. I., Narasimhulu, K. V., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2011) ENDOR/HYSCORE studies of the common intermediate trapped during nitrogenase reduction of N2H2, CH3N2H, and N2H4 support an alternating reaction pathway for N2 reduction. J. Am. Chem. Soc. 133, 11655–11664.

92. Doan, P. E., Telser, J., Barney, B. M., Igarashi, R. Y., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2011) 57Fe ENDOR spectroscopy and “electron inventory” analysis of the nitrogenase E4 intermediate suggest the metal-ion core of FeMo-cofactor cycles through only one redox couple. J. Am. Chem. Soc. 133, 17329–17340.

91. Danyal, K., Yang, Z.-Y., and Seefeldt, L. C. (2011) Electron paramagnetic resonance spectroscopy. Methods Mol. Biol. 766, 191–205.

90. Danyal, K., Dean, D. R., Hoffman, B. M., and Seefeldt, L. C. (2011) Electron transfer within nitrogenase: evidence for a deficit-spending mechanism. Biochemistry 50, 9255–9263.

89. Sarma, R., Barney, B. M., Keable, S., Dean, D. R., Seefeldt, L. C., and Peters, J. W. (2010) Insights into substrate binding at FeMo-cofactor in nitrogenase from the structure of an [alpha]-70Ile MoFe protein variant. J. Inorg. Biochem. 104, 385–389.

88. Lukoyanov, D., Yang, Z.-Y., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2010) Is Mo involved in hydride binding by the four-electron reduced (E4) intermediate of the nitrogenase MoFe protein? J. Am. Chem. Soc. 132, 2526–2527.

87. Danyal, K., Mayweather, D., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2010) Conformational gating of electron transfer from the nitrogenase Fe protein to MoFe protein. J. Am. Chem. Soc. 132, 6894–6895.

86. Danyal, K., Inglet, B. S., Vincent, K. A., Barney, B. M., Hoffman, B. M., Armstrong, F. A., Dean, D. R., and Seefeldt, L. C. (2010) Uncoupling nitrogenase: catalytic reduction of hydrazine to ammonia by a MoFe protein in the absence of Fe protein-ATP. J. Am. Chem. Soc. 132, 13197–13199.

85. Wahlen, B. D., Oswald, W. S., Seefeldt, L. C., and Barney, B. M. (2009) Purification, characterization, and potential bacterial wax production role of an NADPH-dependent fatty aldehyde reductase from Marinobacter aquaeolei VT8. Appl. Environ. Microbiol 75, 2758–2764.

84. Seefeldt, L. C., Hoffman, B. M., and Dean, D. R. (2009) Mechanism of Mo-dependent nitrogenase. Annu. Rev. Biochem. 78, 701–722.

83. Hoffman, B. M., Dean, D. R., and Seefeldt, L. C. (2009) Climbing nitrogenase: toward a mechanism of enzymatic nitrogen fixation. Acc. Chem. Res. 42, 609–619.

82. Harris, D., and Seefeldt, L. (2009) An updated kinetic study of the enzyme lactase for the biochemistry laboratory. J. Chem. Ed. 86, 1271.

81. Barney, B. M., Yurth, M. G., Dos Santos, P. C., Dean, D. R., and Seefeldt, L. C. (2009) A substrate channel in the nitrogenase MoFe protein. J. Biol. Inorg. Chem 14, 1015–1022.

80. Barney, B. M., Lukoyanov, D., Igarashi, R. Y., Laryukhin, M., Yang, T.-C., Dean, D. R., Hoffman, B. M., and Seefeldt, L. C. (2009) Trapping an intermediate of dinitrogen (N2) reduction on nitrogenase. Biochemistry 48, 9094–9102.

79.  Wahlen, B. D., Barney, B. M., and Seefeldt, L. C. (2008) Synthesis of biodiesel from mixed feedstocks and longer chain alcohols using an acid-catalyzed method. Energy Fuels 22, 4223–4228.

78. Sarma, R., Barney, B. M., Hamilton, T. L., Jones, A., Seefeldt, L. C., and Peters, J. W. (2008) Crystal structure of the L protein of Rhodobacter sphaeroides light-independent protochlorophyllide reductase with MgADP bound: a homologue of the nitrogenase Fe protein. Biochemistry 47, 13004–13015.

77. Sarma, R., Mulder, D. W., Brecht, E., Szilagyi, R. K., Seefeldt, L. C., Tsuruta, H., and Peters, J. W. (2007) Probing the MgATP-bound conformation of the nitrogenase Fe protein by solution small-angle X-ray scattering. Biochemistry 46, 14058–14066.

76. Lukoyanov, D., Pelmenschikov, V., Maeser, N., Laryukhin, M., Yang, T. C., Noodleman, L., Dean, D. R., Case, D. A., Seefeldt, L. C., and Hoffman, B. M. (2007) Testing if the interstitial atom, X, of the nitrogenase molybdenum-iron cofactor is N or C: ENDOR, ESEEM, and DFT studies of the S = 3/2 resting state in multiple environments. Inorg. Chem. 46, 11437–11449.

75. Lukoyanov, D., Barney, B. M., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2007) Connecting nitrogenase intermediates with the kinetic scheme for N2 reduction by a relaxation protocol and identification of the N2 binding state. Proc. Natl. Acad. Sci. U.S.A. 104, 1451–1455.

74. Dos Santos, P. C., Mayer, S. M., Barney, B. M., Seefeldt, L. C., and Dean, D. R. (2007) Alkyne substrate interaction within the nitrogenase MoFe protein. J. Inorg. Biochem. 101, 1642–1648.

73. Barney, B. M., McClead, J., Lukoyanov, D., Laryukhin, M., Yang, T.-C., Dean, D. R., Hoffman, B. M., and Seefeldt, L. C. (2007) Diazene (HN=NH) is a substrate for nitrogenase: insights into the pathway of N2 reduction. Biochemistry 46, 6784–6794.

72. Sen, S., Krishnakumar, A., McClead, J., Johnson, M. K., Seefeldt, L. C., Szilagyi, R. K., and Peters, J. W. (2006) Insights into the role of nucleotide-dependent conformational change in nitrogenase catalysis: Structural characterization of the nitrogenase Fe protein Leu127 deletion variant with bound MgATP. J. Inorg. Biochem 100, 1041–1052.

71. Barney, B. M., Lukoyanov, D., Yang, T.-C., Dean, D. R., Hoffman, B. M., and Seefeldt, L. C. (2006) A methyldiazene (HN=N-CH3)-derived species bound to the nitrogenase active-site FeMo cofactor: Implications for mechanism. Proc. Natl. Acad. Sci. U.S.A. 103, 17113–17118.

70.  Barney, B. M., Lee, H.-I., Dos Santos, P. C., Hoffman, B. M., Dean, D. R., and Seefeldt, L. C. (2006) Breaking the N2 triple bond: insights into the nitrogenase mechanism. Dalton Trans 2277–2284.

69. Yang, T.-C., Maeser, N. K., Laryukhin, M., Lee, H.-I., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2005) The interstitial atom of the nitrogenase FeMo-cofactor: ENDOR and ESEEM evidence that it is not a nitrogen. J. Am. Chem. Soc. 127, 12804–12805.

68. Igarashi, R. Y., Laryukhin, M., Dos Santos, P. C., Lee, H.-I., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2005) Trapping H- bound to the nitrogenase FeMo-cofactor active site during H2 evolution: characterization by ENDOR spectroscopy. J. Am. Chem. Soc. 127, 6231–6241.

67. Dos Santos, P. C., Igarashi, R. Y., Lee, H.-I., Hoffman, B. M., Seefeldt, L. C., and Dean, D. R. (2005) Substrate interactions with the nitrogenase active site. Acc. Chem. Res. 38, 208–214.

66. Barney, B. M., Yang, T.-C., Igarashi, R. Y., Dos Santos, P. C., Laryukhin, M., Lee, H.-I., Hoffman, B. M., Dean, D. R., and Seefeldt, L. C. (2005) Intermediates trapped during nitrogenase reduction of N≡N, CH3-N=NH, and H2N-NH2. J. Am. Chem. Soc. 127, 14960–14961.

65. Barney, B. M., Laryukhin, M., Igarashi, R. Y., Lee, H.-I., Dos Santos, P. C., Yang, T.-C., Hoffman, B. M., Dean, D. R., and Seefeldt, L. C. (2005) Trapping a hydrazine reduction intermediate on the nitrogenase active site. Biochemistry 44, 8030–8037.

64. Sen, S., Igarashi, R., Smith, A., Johnson, M. K., Seefeldt, L. C., and Peters, J. W. (2004) A conformational mimic of the MgATP-bound “on state” of the nitrogenase iron protein. Biochemistry 43, 1787–1797.

63. Seefeldt, L. C., Dance, I. G., and Dean, D. R. (2004) Substrate interactions with nitrogenase: Fe versus Mo. Biochemistry 43, 1401–1409.

62. Lee, H.-I., Igarashi, R. Y., Laryukhin, M., Doan, P. E., Dos Santos, P. C., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2004) An organometallic intermediate during alkyne reduction by nitrogenase. J. Am. Chem. Soc. 126, 9563–9569.

61. Jang, S. B., Jeong, M. S., Seefeldt, L. C., and Peters, J. W. (2004) Structural and biochemical implications of single amino acid substitutions in the nucleotide-dependent switch regions of the nitrogenase Fe protein from Azotobacter vinelandii. J. Biol. Inorg. Chem 9, 1028–1033.

60. Igarashi, R. Y., Dos Santos, P. C., Niehaus, W. G., Dance, I. G., Dean, D. R., and Seefeldt, L. C. (2004) Localization of a catalytic intermediate bound to the FeMo-cofactor of nitrogenase. J. Biol. Chem 279, 34770–34775.

59. Barney, B. M., Igarashi, R. Y., Dos Santos, P. C., Dean, D. R., and Seefeldt, L. C. (2004) Substrate interaction at an iron-sulfur face of the FeMo-cofactor during nitrogenase catalysis. J. Biol. Chem. 279, 53621–53624.

58. Sørlie, M., Chan, J. M., Wang, H., Seefeldt, L. C., and Parker, V. D. (2003) Elucidating thermodynamic parameters for electron transfer proteins using isothermal titration calorimetry: application to the nitrogenase Fe protein. J. Biol. Inorg. Chem 8, 560–566.

56. Lee, H.-I., Benton, P. M. C., Laryukhin, M., Igarashi, R. Y., Dean, D. R., Seefeldt, L. C., and Hoffman, B. M. (2003) The interstitial atom of the nitrogenase FeMo-cofactor: ENDOR and ESEEM show it is not an exchangeable nitrogen. J. Am. Chem. Soc. 125, 5604–5605.

55. Igarashi, R. Y., and Seefeldt, L. C. (2003) Nitrogen fixation: the mechanism of the Mo-dependent nitrogenase. Crit. Rev. Biochem. Mol. Biol 38, 351–384.

54. Benton, P. M. C., Laryukhin, M., Mayer, S. M., Hoffman, B. M., Dean, D. R., and Seefeldt, L. C. (2003) Localization of a substrate binding site on the FeMo-cofactor in nitrogenase: trapping propargyl alcohol with an alpha-70-substituted MoFe protein. Biochemistry 42, 9102–9109.

53. Christiansen, J., Dean, D. R., and Seefeldt, L. C. (2001) Mechanistic features of the Mo-containing nitrogenase. Annu. Rev. Plant Physiol. Plant Mol. Biol52, 269–295.

52. Chiu, H., Peters, J. W., Lanzilotta, W. N., Ryle, M. J., Seefeldt, L. C., Howard, J. B., and Rees, D. C. (2001) MgATP-Bound and nucleotide-free structures of a nitrogenase protein complex between the Leu 127 Delta-Fe-protein and the MoFe-protein. Biochemistry 40, 641–650.

51.  Benton, P. M. C., Mayer, S. M., Shao, J., Hoffman, B. M., Dean, D. R., and Seefeldt, L. C. (2001) Interaction of Acetylene and Cyanide with the Resting State of Nitrogenase α-96-Substituted MoFe Proteins†. Biochemistry 40, 13816–13825.

50. Benton, P. M., Christiansen, J., Dean, D. R., and Seefeldt, L. C. (2001) Stereospecificity of acetylene reduction catalyzed by nitrogenase. J. Am. Chem. Soc123, 1822–1827.

49. Sørlie, M., Seefeldt, L. C., and Parker, V. D. (2000) Use of stopped-flow spectrophotometry to establish midpoint potentials for redox proteins. Anal. Biochem 287, 118–125.

48. Ryle, M. J., and Seefeldt, L. C. (2000) Hydrolysis of nucleoside triphosphates other than ATP by nitrogenase. J. Biol. Chem 275, 6214–6219.

47. Ryle, M. J., Lee, H. I., Seefeldt, L. C., and Hoffman, B. M. (2000) Nitrogenase reduction of carbon disulfide: freeze-quench EPR and ENDOR evidence for three sequential intermediates with cluster-bound carbon moieties. Biochemistry 39, 1114–1119.

46. Jang, S. B., Seefeldt, L. C., and Peters, J. W. (2000) Modulating the midpoint potential of the [4Fe-4S] cluster of the nitrogenase Fe protein. Biochemistry39, 641–648.

45. Jang, S. B., Seefeldt, L. C., and Peters, J. W. (2000) Insights into nucleotide signal transduction in nitrogenase: structure of an iron protein with MgADP bound. Biochemistry 39, 14745–14752.

44. Christiansen, J., Seefeldt, L. C., and Dean, D. R. (2000) Competitive substrate and inhibitor interactions at the physiologically relevant active site of nitrogenase. J. Biol. Chem. 275, 36104–36107.

43. Christiansen, J., Chan, J. M., Seefeldt, L. C., and Dean, D. R. (2000) The role of the MoFe protein alpha-125Phe and beta-125Phe residues in Azotobacter vinelandii MoFe protein-Fe protein interaction. J. Inorg. Biochem 80, 195–204.

42. Christiansen, J., Cash, V. L., Seefeldt, L. C., and Dean, D. R. (2000) Isolation and characterization of an acetylene-resistant nitrogenase. J. Biol. Chem.275, 11459–11464.

41. Chan, J. M., Wu, W., Dean, D. R., and Seefeldt, L. C. (2000) Construction and characterization of a heterodimeric iron protein: defining roles for adenosine triphosphate in nitrogenase catalysis. Biochemistry 39, 7221–7228.

40. Lanzilotta, W. N., Parker, V. D., and Seefeldt, L. C. (1999) Thermodynamics of nucleotide interactions with the Azotobacter vinelandii nitrogenase iron protein. Biochim. Biophys. Acta 1429, 411–421.

39. Chan, J. M., Ryle, M. J., and Seefeldt, L. C. (1999) Evidence that MgATP accelerates primary electron transfer in a Clostridium pasteurianum Fe protein-Azotobacter vinelandii MoFe protein nitrogenase tight complex. J. Biol. Chem 274, 17593–17598.

38. Chan, J. M., Christiansen, J., Dean, D. R., and Seefeldt, L. C. (1999) Spectroscopic evidence for changes in the redox state of the nitrogenase P-cluster during turnover. Biochemistry 38, 5779–5785.

37. Peters, J. W., Lanzilotta, W. N., Lemon, B. J., and Seefeldt, L. C. (1998) X-ray crystal structure of the Fe-only hydrogenase (CpI) from Clostridium pasteurianum to 1.8 angstrom resolution. Science 282, 1853–1858.

36. Lanzilotta, W. N., Parker, V. D., and Seefeldt, L. C. (1998) Electron transfer in nitrogenase analyzed by Marcus theory: evidence for gating by MgATP. Biochemistry 37, 399–407.

35.  Lanzilotta, W. N., Christiansen, J., Dean, D. R., and Seefeldt, L. C. (1998) Evidence for coupled electron and proton transfer in the [8Fe-7S] cluster of nitrogenase. Biochemistry 37, 11376–11384.

34. Christiansen, J., Goodwin, P. J., Lanzilotta, W. N., Seefeldt, L. C., and Dean, D. R. (1998) Catalytic and biophysical properties of a nitrogenase Apo-MoFe protein produced by a nifB-deletion mutant of Azotobacter vinelandii. Biochemistry 37, 12611–12623.

33. Seefeldt, L. C., and Dean, D. R. (1997) Role of nucleotides in nitrogenase catalysis. Acc. Chem. Res 30, 260–266.

32.  Rasche, M. E., and Seefeldt, L. C. (1997) Reduction of thiocyanate, cyanate, and carbon disulfide by nitrogenase: kinetic characterization and EPR spectroscopic analysis. Biochemistry 36, 8574–8585.

31.  Parker, V. D., and Seefeldt, L. C. (1997) A mediated thin-layer voltammetry method for the study of redox protein electrochemistry. Anal. Biochem 247, 152–157.

30.  Parker, V. D., Roddick, A., Seefeldt, L. C., Wang, H., and Zheng, G. (1997) Determination of rate and equilibrium constants for the reactions between electron transfer mediators and proteins by linear sweep voltammetry. Anal. Biochem 249, 212–218.

29. Liu, Y., Seefeldt, L. C., and Parker, V. D. (1997) Entropies of redox reactions between proteins and mediators: the temperature dependence of reversible electrode potentials in aqueous buffers. Anal. Biochem 250, 196–202.

28. Lanzilotta, W. N., and Seefeldt, L. C. (1997) Changes in the midpoint potentials of the nitrogenase metal centers as a result of iron protein-molybdenum-iron protein complex formation. Biochemistry 36, 12976–12983.

27. Lanzilotta, W. N., Fisher, K., and Seefeldt, L. C. (1997) Evidence for electron transfer-dependent formation of a nitrogenase iron protein-molybdenum-iron protein tight complex. The role of aspartate 39. J. Biol. Chem 272, 4157–4165.

26. Ryle, M. J., and Seefeldt, L. C. (1996) The [4Fe-4S] cluster domain of the nitrogenase iron protein facilitates conformational changes required for the cooperative binding of two nucleotides. Biochemistry 35, 15654–15662.

25. Ryle, M. J., and Seefeldt, L. C. (1996) Elucidation of a MgATP signal transduction pathway in the nitrogenase iron protein: formation of a conformation resembling the MgATP-bound state by protein engineering. Biochemistry 35, 4766–4775.

24. Ryle, M. J., Lanzilotta, W. N., and Seefeldt, L. C. (1996) Elucidating the mechanism of nucleotide-dependent changes in the redox potential of the [4Fe-4S] cluster in nitrogenase iron protein: the role of phenylalanine 135. Biochemistry 35, 9424–9434.

23. Ryle, M. J., Lanzilotta, W. N., Seefeldt, L. C., Scarrow, R. C., and Jensen, G. M. (1996) Circular dichroism and x-ray spectroscopies of Azotobacter vinelandii nitrogenase iron protein. MgATP and MgADP induced protein conformational changes affecting the [4Fe-4S] cluster and characterization of a [2Fe-2S] form. J. Biol. Chem 271, 1551–1557.

22. Lanzilotta, W. N., and Seefeldt, L. C. (1996) Electron transfer from the nitrogenase iron protein to the [8Fe-(7/8)S] clusters of the molybdenum-iron protein. Biochemistry 35, 16770–16776.

21. Lanzilotta, W. N., Fisher, K., and Seefeldt, L. C. (1996) Evidence for electron transfer from the nitrogenase iron protein to the molybdenum-iron protein without MgATP hydrolysis: characterization of a tight protein-protein complex. Biochemistry 35, 7188–7196.

20. Seefeldt, L. C., Rasche, M. E., and Ensign, S. A. (1995) Carbonyl sulfide and carbon dioxide as new substrates, and carbon disulfide as a new inhibitor, of nitrogenase. Biochemistry 34, 5382–5389.

19. Ryle, M. J., Lanzilotta, W. N., Mortenson, L. E., Watt, G. D., and Seefeldt, L. C. (1995) Evidence for a central role of lysine 15 of Azotobacter vinelandiinitrogenase iron protein in nucleotide binding and protein conformational changes. J. Biol. Chem 270, 13112–13117.

18. Lanzilotta, W. N., Ryle, M. J., and Seefeldt, L. C. (1995) Nucleotide hydrolysis and protein conformational changes in Azotobacter vinelandii nitrogenase iron protein: defining the function of aspartate 129. Biochemistry 34, 10713–10723.

17. Lanzilotta, W. N., Holz, R. C., and Seefeldt, L. C. (1995) Proton NMR investigation of the [4Fe–4S]1+ cluster environment of nitrogenase iron protein from Azotobacter vinelandii: defining nucleotide-induced conformational changes. Biochemistry 34, 15646–15653.

16. Chen, J. C., Mortenson, L. E., and Seefeldt, L. C. (1995) Analysis of a gene region required for dihydrogen oxidation in Azotobacter vinelandii. Curr. Microbiol 30, 351–355.

15.Seefeldt, L. C. (1994) Docking of nitrogenase iron- and molybdenum-iron proteins for electron transfer and MgATP hydrolysis: the role of arginine 140 and lysine 143 of the Azotobacter vinelandii iron protein. Protein Sci 3, 2073–2081.

14. Seefeldt, L. C., and Ensign, S. A. (1994) A continuous, spectrophotometric activity assay for nitrogenase using the reductant titanium(III) citrate. Anal. Biochem 221, 379–386.

13.Seefeldt, L. C., and Mortenson, L. E. (1993) Increasing nitrogenase catalytic efficiency for MgATP by changing serine 16 of its Fe protein to threonine: use of Mn2+ to show interaction of serine 16 with Mg2+. Protein Sci 2, 93–102.

12. Mortenson, L. E., Seefeldt, L. C., Morgan, T. V., and Bolin, J. T. (1993) The role of metal clusters and MgATP in nitrogenase catalysis. Adv. Enzymol. Relat. Areas Mol. Biol 67, 299–374.

11. Seefeldt, L. C., Morgan, T. V., Dean, D. R., and Mortenson, L. E. (1992) Mapping the site(s) of MgATP and MgADP interaction with the nitrogenase of Azotobacter vinelandii. Lysine 15 of the iron protein plays a major role in MgATP interaction. J. Biol. Chem 267, 6680–6688.

10. Hyman, M. R., Seefeldt, L. C., Morgan, T. V., Arp, D. J., and Mortenson, L. E. (1992) Kinetic and spectroscopic analysis of the inactivating effects of nitric oxide on the individual components of Azotobacter vinelandii nitrogenase. Biochemistry 31, 2947–2955.

9.Ford, C. M., Garg, N., Garg, R. P., Tibelius, K. H., Yates, M. G., Arp, D. J., and Seefeldt, L. C. (1990) The identification, characterization, sequencing and mutagenesis of the genes (hupSL) encoding the small and large subunits of the H2-uptake hydrogenase of Azotobacter chroococcum. Mol. Microbiol 4, 999–1008.

8. Seefeldt, L. C., and Arp, D. J. (1989) Oxygen effects on the nickel- and iron-containing hydrogenase from Azotobacter vinelandii. Biochemistry 28, 1588–1596.

7.Seefeldt, L. C., and Arp, D. J. (1989) Cyanide inactivation of hydrogenase from Azotobacter vinelandii. J. Bacteriol 171, 3298–3303.

6. Kovacs, K. L., Seefeldt, L. C., Tigyi, G., Doyle, C. M., Mortenson, L. E., and Arp, D. J. (1989) Immunological relationship among hydrogenases. J. Bacteriol171, 430–435.

5. Hyman, M. R., Seefeldt, L. C., and Arp, D. J. (1988) Aerobic, inactive forms of Azotobacter vinelandii hydrogenase: activation kinetics and insensitivity to C2H2 inhibition. Biochim. Biophys. Acta 957, 91–96.

4. Seefeldt, L. C., and Arp, D. J. (1987) Redox-dependent subunit dissociation of Azotobacter vinelandii hydrogenase in the presence of sodium dodecyl sulfate. J. Biol. Chem 262, 16816–16821.

3. Seefeldt, L. C., Fox, C. A., and Arp, D. J. (1986) Reversible inactivation of the O2-labile hydrogenases from Azotobacter vinelandii and Rhizobium japonicum. J. Biol. Chem 261, 10688–10694.

2. Seefeldt, L. C., and Arp, D. J. (1986) Purification to homogeneity of Azotobacter vinelandii hydrogenase: a nickel and iron containing alpha beta dimer. Biochimie 68, 25–34.

1. Arp, D. J., McCollum, L. C., and Seefeldt, L. C. (1985) Molecular and immunological comparison of membrane-bound, H2-oxidizing hydrogenases of Bradyrhizobium japonicum, Alcaligenes eutrophus, Alcaligenes latus, and Azotobacter vinelandii. J. Bacteriol 163, 15–20.