scholarly journals Comment on “Structural evidence for a dynamic metallocofactor during N2 reduction by Mo-nitrogenase”

Science ◽  
2021 ◽  
Vol 371 (6530) ◽  
pp. eabe5481 ◽  
Author(s):  
John W. Peters ◽  
Oliver Einsle ◽  
Dennis R. Dean ◽  
Serena DeBeer ◽  
Brian M. Hoffman ◽  
...  
Keyword(s):  
Active Site ◽  
Biochemical Evidence ◽  
Mofe Protein ◽  
Femo Cofactor

Kang et al. (Reports, 19 June 2020, p. 1381) report a structure of the nitrogenase MoFe protein that is interpreted to indicate binding of N2 or an N2-derived species to the active-site FeMo cofactor. Independent refinement of the structure and consideration of biochemical evidence do not support this claim.

Strategies for the Functional Analysis of the Azotobacter Vinelandii MoFe Protein and its Active Site FeMo-Cofactor

2004 ◽  
pp. 141-159
Author(s):  
S. M. Mayer ◽  
P. C. Dos Santos ◽  
L. C. Seefeldt ◽  
D. R. Dean
Keyword(s):  
Functional Analysis ◽  
Active Site ◽  
Azotobacter Vinelandii ◽  
Mofe Protein ◽  
Femo Cofactor

scholarly journals Evidence for a dynamic role for homocitrate during nitrogen fixation: the effect of substitution at the α-Lys426 position in MoFe-protein of Azotobacter vinelandii

2006 ◽  
Vol 397 (2) ◽  
pp. 261-270 ◽  
Author(s):  
Marcus C. Durrant ◽  
Amanda Francis ◽  
David J. Lowe ◽  
William E. Newton ◽  
Karl Fisher
Keyword(s):  
Active Site ◽  
Ring Opening ◽  
Azotobacter Vinelandii ◽  
Chelate Ring ◽  
Wild Type ◽  
Biologically Relevant ◽  
Mofe Protein ◽  
Key Players ◽  
Femo Cofactor ◽  
The Subject

Although it is generally accepted that the active site of nitrogenase is located on the FeMo-cofactor, the exact site(s) of N2 binding and reduction remain the subject of continuing debate, with both molybdenum and iron atoms being suggested as key players. The current consensus favours binding of acetylene and some other non-biologically relevant substrates to the central iron atoms of the FeMo-cofactor [Dos Santos, Igarashi, Lee, Hoffman, Seefeldt and Dean (2005) Acc. Chem. Res. 38, 208–214]. The reduction of N2 is, however, a more demanding process than reduction of these alternative substrates because it has a much higher activation energy and does not bind until three electrons have been accumulated on the enzyme. The possible conversion of bidentate into monodentate homocitrate on this three electron-reduced species has been proposed to free up a binding site for N2 on the molybdenum atom. One of the features of this hypothesis is that α-Lys426 facilitates chelate ring opening and subsequent orientation of the monodentate homocitrate by forming a specific hydrogen bond to the homocitrate -CH2CH2CO2− carboxylate group. In support of this concept, we show that mutation of α-Lys426 can selectively perturb N2 reduction without affecting acetylene reduction. We interpret our experimental observations in the light of a detailed molecular mechanics modelling study of the wild-type and altered MoFe-nitrogenases.

Exploring the Role of the Central Carbide of the Nitrogenase Active-Site FeMo-cofactor through Targeted 13C Labeling and ENDOR Spectroscopy

2021 ◽  
Author(s):  
Ana Pérez-González ◽  
Zhi-Yong Yang ◽  
Dmitriy A. Lukoyanov ◽  
Dennis R. Dean ◽  
Lance C. Seefeldt ◽  
...  
Keyword(s):  
Active Site ◽  
13C Labeling ◽  
Endor Spectroscopy ◽  
Femo Cofactor

Role of the MoFe Protein .alpha.-Subunit Histidine-195 Residue in FeMo-cofactor Binding and Nitrogenase Catalysis

Biochemistry ◽  
1995 ◽  
Vol 34 (9) ◽  
pp. 2798-2808 ◽  
Author(s):  
Chul-Hwan Kim ◽  
William E. Newton ◽  
Dennis R. Dean
Keyword(s):  
Alpha Subunit ◽  
Cofactor Binding ◽  
Mofe Protein ◽  
Femo Cofactor ◽  
Protein Alpha Subunit

scholarly journals Exploring Electron/Proton Transfer and Conformational Changes in the Nitrogenase MoFe Protein and FeMo-cofactor Through Cryoreduction/EPR Measurements

2016 ◽  
Vol 56 (9-10) ◽  
pp. 841-851 ◽  
Author(s):  
Roman Davydov ◽  
Nimesh Khadka ◽  
Zhi-Yong Yang ◽  
Andrew J. Fielding ◽  
Dmitriy Lukoyanov ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Conformational Changes ◽  
Mofe Protein ◽  
Femo Cofactor ◽  
Epr Measurements ◽  
Electron Proton Transfer

Nitrogenase MoFe-Protein at 1.16 A Resolution: A Central Ligand in the FeMo-Cofactor

Science ◽  
2002 ◽  
Vol 297 (5587) ◽  
pp. 1696-1700 ◽  
Author(s):  
O. Einsle
Keyword(s):  
Mofe Protein ◽  
Femo Cofactor

scholarly journals Nitrogenase from nifV mutants of Klebsiella pneumoniae contains an altered form of the iron-molybdenum cofactor

1984 ◽  
Vol 217 (1) ◽  
pp. 317-321 ◽  
Author(s):  
T R Hawkes ◽  
P A McLean ◽  
B E Smith
Keyword(s):  
Klebsiella Pneumoniae ◽  
Active Site ◽  
Molybdenum Cofactor ◽  
Wild Type ◽  
H2 Evolution ◽  
Mofe Protein ◽  
Fe Protein ◽  
Metal Contents ◽  
Altered Form ◽  
Iron Molybdenum Cofactor

When the iron-molybdenum cofactor (FeMoco) was extracted from the MoFe protein of nitrogenase from a nifV mutant of Klebsiella pneumoniae and combined with the FeMoco-deficient MoFe protein from a nifB mutant, the resultant MoFe protein exhibited the NifV phenotype, i.e. in combination with wild-type Fe protein it exhibited poor N2-fixation activity and its H2-evolution activity was inhibited by CO. These data provide strong evidence that FeMoco contains the active site of nitrogenase. The metal contents and e.p.r. properties of FeMoco from wild-type and nifV mutants of K. pneumoniae are very similar.

scholarly journals Nitrogenase from Klebsiella pneumoniae. An e.p.r. signal observed during enzyme turnover under ethylene is associated with the iron-molybdenum cofactor

1983 ◽  
Vol 211 (2) ◽  
pp. 495-497 ◽  
Author(s):  
T R Hawkes ◽  
D J Lowe ◽  
B E Smith
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Klebsiella Pneumoniae ◽  
Isotopic Substitution ◽  
Resonance Signal ◽  
Paramagnetic Resonance ◽  
Mofe Protein ◽  
Femo Cofactor ◽  
Enzyme Turnover ◽  
Iron Molybdenum Cofactor ◽  
Electron Paramagnetic

During turnover at 10 degrees C at pH 7.4 in the presence of ethylene, the MoFe protein of Klebsiella pneumoniae nitrogenase (Kp 1) exhibited an electron-paramagnetic-resonance signal with g-values at 2.12, 1.998 and 1.987. 57Fe isotopic substitution demonstrated that this signal arose from the Kp 1 FeMo-cofactor in an S = 1/2 spin state.

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