1994-2004 Publications

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 Science 3, 2073-2081.

16. 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.

17. 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 vinelandii nitrogenase 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 the Azotobacter vinelandii nitrogenase iron protein: Defining the function of aspartate 129. Biochemistry 34, 10713-10723.

19. 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.

20. 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.

21. 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. 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.

23. 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.

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.

25. 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.

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

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.

28. Seefeldt, L.C. and Dean, D.R. 1997. Role of nucleotides in nitrogenase catalysis. Acc. Chem. Res. 30, 260-266.

29. 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. 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., 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.

32. 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.

33. 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.

34. 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.

36. 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.

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

38. 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., 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.

40. 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.

41. 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. Biochemistry 39, 641-648.

42. Christiansen, J., Chan, J.M., Seefeldt, L.C., and Dean, D.R. 2000. The role of the MoFe protein ?-125Phe and ?-125Phe residues in Azotobacter vinelandii MoFe protein-Fe protein interactions. J. Inorg. Biochem. 80, 195-204.

43. Christiansen, J., Cash, V.L., Seefeldt, L.C., Dean, D.R. 2000. Isolationi and characterization of an acetylene resistant nitrogenase. J. Biol. Chem. 275, 11459-11464.

44. 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.

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

46. Chan, J.M., Wu, W., Dean, D.R., and Seefeldt, L.C. 2000. Construction and characterization of a heterodimeric Fe protein: Defining roles for ATP in nitrogenase catalysis. Biochemistry 39, 7221-7228.

47. 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.

48. 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.

49. Sorlie, 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.

50. Chiu, H.J., 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 Leu 127?-Fe protein and the MoFe protein. Biochemistry 40, 641-650.

51. Benton, P.M.C., Christiansen, J., Dean, D.R., and Seefeldt, L.C. 2001. Stereospecificity of acetylene reduction catalyzed by nitrogenase. J. Amer. Chem. Soc. 123, 1822-1827.

52. 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 ?-96-substituted MoFe proteins. Biochemistry 40,13816-13825.

53. Sorlie, 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.

54. 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. 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 FeMo-cofactor in nitrogenase: Trapping propargyl alcohol with an ?-70-substituted MoFe protein. Biochemistry 42, 9102-9109.

56. 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.

57. Seefeldt, L.C., Dance, I., and Dean, D.R. 2004. Substrate interactions with nitrogenase: Fe versus Mo. Biochemistry 43, 1401-1409.

58. 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 Fe protein. Biochemistry 43, 1787-1797.

59. Igarashi, R.Y., Dos Santos, P.C., Niehaus, W.G., Dance, I., 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.

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

62. Jang, S.B., Jeong, M.S., Seefeldt, L.C., 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.

63. Dos Santos, P.C., Igarashi, R.Y., Lee, H.I., Hoffman, B.M., Seefeldt, L.C., Dean, D.R. Substrate interactions with the nitrogenase active site. Acc. Chem. Res. (in press).

64. Igarashi, R.Y., Laryukhin, M., Dos Santos, P.C., Lee, H.I, Dean, D.R., Seefeldt, L.C., Hoffman, B.M. Trapping H- bound to the nitrogenase FeMo-cofactor active site during H2 evolution: Characterization by ENDOR spectroscopy. J. Am. Chem. Soc. (in press).

Funding