scholarly journals Comparison of the iron proteins from the nitrogen fixation complexes of Azotobacter vinelandii, Clostridium pasteurianum, and Klebsiella pneumoniae

1980 ◽  
Vol 77 (7) ◽  
pp. 3826-3830 ◽  
Author(s):  
R. P. Hausinger ◽  
J. B. Howard
Keyword(s):  
Nitrogen Fixation ◽  
Klebsiella Pneumoniae ◽  
Azotobacter Vinelandii ◽  
Clostridium Pasteurianum ◽  
Iron Proteins

Nitrogen fixation by cell-free extracts of Klebsiella pneumoniae

1968 ◽  
Vol 14 (1) ◽  
pp. 33-38 ◽  
Author(s):  
M. C. Mahl ◽  
P. W. Wilson
Keyword(s):  
Nitrogen Fixation ◽  
Klebsiella Pneumoniae ◽  
Azotobacter Vinelandii ◽  
Ammonium Ion ◽  
Michaelis Constant ◽  
Nitrogen Gas ◽  
Aerobacter Aerogenes ◽  
Free System ◽  
Evolving System ◽  
A Cell

A cell-free system which permits nitrogen fixation by extracts of Klebsiella pneumoniae M5al (formerly Aerobacter aerogenes) has been developed. It is, essentially, that system described by Bulen and associates for Azotobacter vinelandii, utilizing ATP as a source of energy and dithionite as a source of electrons. The Michaelis constant for fixation has been estimated to be 0.12 atm. The extracts possessed an ATP-dependent hydrogen evolving system. Hydrogen evolution from these extracts was less under nitrogen than under helium in the presence of ATP. Nitrogen gas appears to be the inducer of nitrogen fixation. In the absence of N2, no induction of nitrogenase occurs. Nitrogenase is absent in cells grown on NH4+-N. There is a lag of about 13 h after the introduction of N2 gas into a culture which has depleted its supply of NH4+-N before nitrogenase can be detected. For reasons discussed in the text, this conclusion must be regarded as tentative at this time. Ammonium ion appears to prevent the synthesis of new molecules of nitrogenase without affecting the activity of those already formed.

Conformational variability in structures of the nitrogenase iron proteins from Azotobacter vinelandii and Clostridium pasteurianum

1998 ◽  
Vol 280 (4) ◽  
pp. 669-685 ◽  
Author(s):  
Jamie L Schlessman ◽  
Deborah Woo ◽  
Leemor Joshua-Tor ◽  
James B Howard ◽  
Douglas C Rees
Keyword(s):  
Azotobacter Vinelandii ◽  
Clostridium Pasteurianum ◽  
Iron Proteins ◽  
Conformational Variability

Regulation of nitrogenase synthesis by Klebsiella pneumoniae

1970 ◽  
Vol 16 (8) ◽  
pp. 681-685 ◽  
Author(s):  
R. A. Parejko ◽  
P. W. Wilson
Keyword(s):  
Klebsiella Pneumoniae ◽  
Rhodospirillum Rubrum ◽  
Azotobacter Vinelandii ◽  
Clostridium Pasteurianum ◽  
Apparent Absence

The synthesis of the nitrogenase system in N2-fixing bacteria is repressed when the organisms are grown on NH4+-N. It has not been unequivocally determined, however, if N2 is necessary for induction in NH4+-deficient cultures. Previous experiments with Klebsiella pneumoniae, Azotobacter vinelandii, Clostridium pasteurianum, and Rhodospirillum rubrum have been inconclusive owing to inadequacy of the methods, primarily the presence of N2 as a contaminant in the gases used. Results of experiments described in this paper using cultures of K. pneumoniae M5a1 grown under both limited N2 and in its apparent absence indicate that the control of nitrogenase is most likely through simple repression by NH4+ or by an incorporation product, e.g., glutamine.

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