Characterization of a tungsten-substituted nitrogenase isolated from Rhodobacter capsulatus

Siemann S, Schneider K, Oley M, Müller A (2003)
BIOCHEMISTRY 42(13): 3846-3857.

Zeitschriftenaufsatz | Veröffentlicht | Englisch
 
Download
Es wurden keine Dateien hochgeladen. Nur Publikationsnachweis!
Autor*in
Abstract / Bemerkung
In the phototrophic non-sulfur bacterium Rhodobacter capsulatus, the biosynthesis of the conventional Mo-nitrogenase is strictly Mo-regulated. Significant amounts of both dinitrogenase and dinitrogenase reductase were only formed when the growth medium was supplemented with molybdate (I muM). During cell growth under Mo-deficient conditions, tungstate, at high concentrations (I mM), was capable of partially (similar to25%) substituting for molybdate in the induction of nitrogenase synthesis. On the basis of such conditions, a tungsten-substituted nitrogenase was isolated from R. capsulatus with the aid of anfA (Fe-only nitrogenase defective) mutant cells and partially purified by Q-sepharose chromatography. Metal analyses revealed the protein to contain an average of I W-, 16 Fe-, and less than 0.01 Mo atoms per alpha(2)beta(2)-tetramer. The tungsten-substituted (WFe) protein was inactive in reducing N-2 and marginally active in acetylene reduction, but it was found to show considerable activity with respect to the generation of H-2 from protons. The EPR spectrum of the WFe protein, recorded at 4 K, exhibited three distinct signals: (i) an S = 3/2 signal, which dominates the low-field region of the spectrum (g = 4.19, 3.93) and is indicative of a tungsten-substituted cofactor (termed FeWco), (ii) a marginal S = 3/2 signal (g = 4.29, 3.67) that can be attributed to residual amounts of FeMoco present in the protein, and (iii) a broad S = 1/2 signal (g = 2.09, 1.95, 1.86) arising from at least two paramagnetic species. Redox titrational analysis of the WFe protein revealed the midpoint potential of the FeWco (E-m < -200 mV) to be shifted to distinctly lower potentials as compared to that of the FeMoco (E-m similar to -50 mV) present in the native enzyme. The P clusters of both the WFe and the MoFe protein appear indistinguishable with respect to their midpoint potentials. EPR spectra recorded with the WFe protein under turnover conditions exhibited a 20% decrease in the intensity of the FeWco signal, indicating that the cofactor can be enzymatically reduced only to a small extent. The data presented in the current study demonstrate the pivotal role of molybdenum in optimal N-2 fixation and provides direct evidence that the inability of a tungsten-substituted nitrogenase to reduce N-2 is due to the difficulty to effectively reduce the FeW cofactor beyond its semireduced state.
Erscheinungsjahr
2003
Zeitschriftentitel
BIOCHEMISTRY
Band
42
Ausgabe
13
Seite(n)
3846-3857
ISSN
0006-2960
eISSN
1520-4995
Page URI
https://pub.uni-bielefeld.de/record/1612149

Zitieren

Siemann S, Schneider K, Oley M, Müller A. Characterization of a tungsten-substituted nitrogenase isolated from Rhodobacter capsulatus. BIOCHEMISTRY. 2003;42(13):3846-3857.
Siemann, S., Schneider, K., Oley, M., & Müller, A. (2003). Characterization of a tungsten-substituted nitrogenase isolated from Rhodobacter capsulatus. BIOCHEMISTRY, 42(13), 3846-3857. doi:10.1021/bi0270790
Siemann, S., Schneider, K., Oley, M., and Müller, A. (2003). Characterization of a tungsten-substituted nitrogenase isolated from Rhodobacter capsulatus. BIOCHEMISTRY 42, 3846-3857.
Siemann, S., et al., 2003. Characterization of a tungsten-substituted nitrogenase isolated from Rhodobacter capsulatus. BIOCHEMISTRY, 42(13), p 3846-3857.
S. Siemann, et al., “Characterization of a tungsten-substituted nitrogenase isolated from Rhodobacter capsulatus”, BIOCHEMISTRY, vol. 42, 2003, pp. 3846-3857.
Siemann, S., Schneider, K., Oley, M., Müller, A.: Characterization of a tungsten-substituted nitrogenase isolated from Rhodobacter capsulatus. BIOCHEMISTRY. 42, 3846-3857 (2003).
Siemann, S, Schneider, Klaus, Oley, M, and Müller, Achim. “Characterization of a tungsten-substituted nitrogenase isolated from Rhodobacter capsulatus”. BIOCHEMISTRY 42.13 (2003): 3846-3857.

13 Zitationen in Europe PMC

Daten bereitgestellt von Europe PubMed Central.

Molecular Mechanisms of Tungsten Toxicity Differ for Glycine max Depending on Nitrogen Regime.
Preiner J, Wienkoop S, Weckwerth W, Oburger E., Front Plant Sci 10(), 2019
PMID: 31001297
Protons and pleomorphs: aerobic hydrogen production in Azotobacters.
Noar JD, Bruno-Bárcena JM., World J Microbiol Biotechnol 32(2), 2016
PMID: 26748806
Protons and pleomorphs: aerobic hydrogen production in Azotobacters
Noar JD, Bruno-Bárcena JM., World J Microbiol Biotechnol 32(2), 2016
PMID: IND604781368
Aerobic Hydrogen Production via Nitrogenase in Azotobacter vinelandii CA6.
Noar J, Loveless T, Navarro-Herrero JL, Olson JW, Bruno-Bárcena JM., Appl Environ Microbiol 81(13), 2015
PMID: 25911479
Tungsten Toxicity in Plants.
Adamakis ID, Panteris E, Eleftheriou EP., Plants (Basel) 1(2), 2012
PMID: 27137642
Multiple roles of siderophores in free-living nitrogen-fixing bacteria.
Kraepiel AM, Bellenger JP, Wichard T, Morel FM., Biometals 22(4), 2009
PMID: 19277875
Molybdenum trafficking for nitrogen fixation.
Hernandez JA, George SJ, Rubio LM., Biochemistry 48(41), 2009
PMID: 19772354
Tungsten, the surprisingly positively acting heavy metal element for prokaryotes.
Andreesen JR, Makdessi K., Ann N Y Acad Sci 1125(), 2008
PMID: 18096847
Complexation of oxoanions and cationic metals by the biscatecholate siderophore azotochelin.
Bellenger JP, Arnaud-Neu F, Asfari Z, Myneni SC, Stiefel EI, Kraepiel AM., J Biol Inorg Chem 12(3), 2007
PMID: 17171370

Export

Markieren/ Markierung löschen
Markierte Publikationen

Open Data PUB

Web of Science

Dieser Datensatz im Web of Science®

Quellen

PMID: 12667075
PubMed | Europe PMC

Suchen in

Google Scholar