+ Site Statistics
References:
52,654,530
Abstracts:
29,560,856
PMIDs:
28,072,755
+ Search Articles
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ PDF Full Text
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Translate
+ Recently Requested

Stoichiometry and spectral properties of the MoFe cofactor and noncofactor redox centers in the MoFe protein of nitrogenase from Azotobacter vinelandii



Stoichiometry and spectral properties of the MoFe cofactor and noncofactor redox centers in the MoFe protein of nitrogenase from Azotobacter vinelandii



Biochemistry 20(25): 7272-7277



Reductive EPR and optical titrations of oxidized MoFe protein using reduced methyl viologen as reductant were used to quantitate the stoichiometry of the various spectroscopically and electrochemically distinct redox centers in the oxidized MoFe protein. Three centers were found to correlate with the EPR signal development (MoFe cofactor centers), and three centers were found to be independent of the EPR signal (P clusters) but to demonstrate distinct optical and kinetic properties. Oxidative EPR and optical titrations of reduced MoFe protein are reported which support the presence of three P-cluster centers. The optical titrations show a distinct change in kinetic behavior between the MoFe cofactor and P-cluster centers. Controlled potential coulometry demonstrates that incremental oxidation of reduced protein by methylene blue, thionine, or indigodisulfonate occurs specifically at three P-cluster sites. Subsequent oxidation by methylene blue and thionine (but not indigodisulfonate) causes the EPR signal to disappear. Three P-cluster sites, two EPR sites, and one presently uncharacterized site are suggested by the results of this study.

(PDF emailed within 1 workday: $29.90)

Accession: 044405285

Download citation: RISBibTeXText

PMID: 6274395


Related references

Nitrogenase XI: Mössbauer studies on the cofactor centers of the MoFe protein from Azotobacter vinelandii OP. Biochimica et Biophysica Acta 576(1): 192-203, 1979

The redox and magnetic properties of the prosthetic groups in the MoFe-protein of Azotobacter vinelandii nitrogenase. Palacios, R, Mora, J, Newton, W E Current Plant Science and Biotechnology in Agriculture; New horizons in nitrogen fixation 137, 1993

Nitrogenase MoFe protein from Clostridium pasteurianum at 1.08 Å resolution: comparison with the Azotobacter vinelandii MoFe protein. Acta Crystallographica. Section D, Biological Crystallography 71(Pt 2): 274-282, 2015

Pre-steady-state analysis of reduced MoFe-protein intermediates generated during enzyme turnover from wild-type and altered Azotobacter vinelandii nitrogenase MoFe-proteins. Finan, Turlough M , Reprint Author, O'Brian, Mark R, Layzell, David B, Vessey, J Kevin, Newton, William Nitrogen fixation: Global perspectives: 369, 2002

Electron paramagnetic resonance analysis of different Azotobacter vinelandii nitrogenase MoFe-protein conformations generated during enzyme turnover: evidence for S = 3/2 spin states from reduced MoFe-protein intermediates. Biochemistry 40(11): 3333-3339, 2001

Nitrogenase X: Mössbauer and EPR studies on reversibly oxidized MoFe protein from Azotobacter vinelandii OP. Nature of the iron centers. Biochimica et Biophysica Acta 537(2): 185-207, 1978

Purification and properties of nitrogenase MoFe protein from a nif Z deletion strain of Azotobacter vinelandii. Acta Botanica Sinica 38(8): 605-611, 1996

The in-vivo identification of the MoFe protein (FeMo cofactor) of nitrogenase in Klebsiella pneumoniae and of the Mo-storage protein in Azotobacter vinelandii via the nuclear quadrupole interaction of 99Mo(b)99Tc. Biochimica et Biophysica Acta - Protein Structure and Molecular Enzymology 1164(3): 311-318, 1993

The in-vivo identification of the MoFe protein (FeMo cofactor) of nitrogenase in Klebsiella pneumoniae and of the Mo-storage protein in Azotobacter vinelandii via the nuclear quadrupole interaction of 99Mo(beta-)99Tc. Biochimica et Biophysica Acta 1164(3): 311-318, 1993

Redox and spectroscopic properties of oxidized MoFe protein from Azotobacter vinelandii. Biochemistry 19(21): 4926-4932, 1980

Redox properties and EPR spectroscopy of the P clusters of Azotobacter vinelandii MoFe protein. European Journal of Biochemistry 212(1): 51-61, 1993

Altered nitrogenase MoFe proteins from Azotobacter vinelandii. Analysis of MoFe proteins having amino acid substitutions for the conserved cysteine residues within the beta-subunit. Biochemical Journal 277: 457-464, 1991

Catalytic and biophysical properties of a nitrogenase Apo-MoFe protein produced by a nifB-deletion mutant of Azotobacter vinelandii. Biochemistry 37(36): 12611-12623, 1998

Nitrogenase: properties of the catalytically inactive complex between the Azotobacter vinelandii MoFe protein and the Clostridium pasteurianum Fe protein. Biochimica et Biophysica Acta 527(2): 359-369, 1978

The inactive MoFe protein (NifB-Kp1) of the nitrogenase from nifB mutants of Klebsiella pneumoniae. Its interaction with FeMo-cofactor and the properties of the active MoFe protein formed. Biochemical Journal 223(3): 783-792, 1984