Diiron dithiolate complexes containing intra-ligand NH⋯S hydrogen bonds: [FeFe] hydrogenase active site models for the electrochemical proton reduction of HOAc with low overpotential

2008 ◽  
pp. 2400 ◽  
Author(s):  
Ze Yu ◽  
Mei Wang ◽  
Ping Li ◽  
Weibing Dong ◽  
Fujun Wang ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Active Site ◽  
Proton Reduction ◽  
Dithiolate Complexes ◽  
Low Overpotential ◽  
Diiron Dithiolate Complexes

On the electrochemistry of diiron dithiolate complexes related to the active site of the [FeFe]H2ase

2008 ◽  
Vol 11 (8) ◽  
pp. 842-851 ◽  
Author(s):  
Jean-François Capon ◽  
Frédéric Gloaguen ◽  
François Y. Pétillon ◽  
Philippe Schollhammer ◽  
Jean Talarmin
Keyword(s):  
Active Site ◽  
Dithiolate Complexes ◽  
Diiron Dithiolate Complexes

Electron-Transfer-Catalyzed Rearrangement of Unsymmetrically Substituted Diiron Dithiolate Complexes Related to the Active Site of the [FeFe]-Hydrogenases

2007 ◽  
Vol 46 (23) ◽  
pp. 9863-9872 ◽  
Author(s):  
Salah Ezzaher ◽  
Jean-François Capon ◽  
Frédéric Gloaguen ◽  
François Y. Pétillon ◽  
Philippe Schollhammer ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Active Site ◽  
Dithiolate Complexes ◽  
Diiron Dithiolate Complexes

Electrochemical Synthesis of Mono- and Disubstituted Diiron Dithiolate Complexes as Models for the Active Site of Iron-Only Hydrogenases

2007 ◽  
Vol 2007 (32) ◽  
pp. 5062-5068 ◽  
Author(s):  
Didier Morvan ◽  
Jean-François Capon ◽  
Frederic Gloaguen ◽  
Philippe Schollhammer ◽  
Jean Talarmin
Keyword(s):  
Active Site ◽  
Electrochemical Synthesis ◽  
Dithiolate Complexes ◽  
Diiron Dithiolate Complexes

Effect of the S-to-S bridge on the redox properties and H2activation performance of diiron complexes related to the [FeFe]-hydrogenase active site

2016 ◽  
Vol 45 (44) ◽  
pp. 17687-17696 ◽  
Author(s):  
Minglun Cheng ◽  
Mei Wang ◽  
Dehua Zheng ◽  
Licheng Sun
Keyword(s):  
Active Site ◽  
Redox Properties ◽  
Dithiolate Complexes ◽  
Diiron Dithiolate Complexes

Studies on diiron dithiolate complexes containing the same PNP ligand but different S-to-S bridges demonstrate that changing the S-to-S bridge can considerably alter the H2activation performance of [FeFe]-hydrogenase models.

Pendant bases as proton transfer relays in diiron dithiolate complexes inspired by [Fe–Fe] hydrogenase active site

2008 ◽  
Vol 693 (17) ◽  
pp. 2828-2834 ◽  
Author(s):  
Zhen Wang ◽  
Wenfeng Jiang ◽  
Jianhui Liu ◽  
Weina Jiang ◽  
Yu Wang ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Active Site ◽  
Dithiolate Complexes ◽  
Diiron Dithiolate Complexes

WHICH IS THE PROTON-SHUTTLE IN ISOXANTHOPTERIN DEAMINASE? QM/MM MD UNDERSTANDING

2013 ◽  
Vol 12 (08) ◽  
pp. 1341002 ◽  
Author(s):  
XIN ZHANG ◽  
MING LEI
Keyword(s):  
Crystal Structure ◽  
Molecular Dynamics ◽  
Hydrogen Bonds ◽  
Proton Transfer ◽  
Glutamic Acid ◽  
Active Site ◽  
Nucleophilic Attack ◽  
Zinc Ions ◽  
Initial Model ◽  
Dynamics Simulations

The deamination process of isoxanthopterin catalyzed by isoxanthopterin deaminase was determined using the combined QM(PM3)/MM molecular dynamics simulations. In this paper, the updated PM3 parameters were employed for zinc ions and the initial model was built up based on the crystal structure. Proton transfer and following steps have been investigated in two paths: Asp336 and His285 serve as the proton shuttle, respectively. Our simulations showed that His285 is more effective than Aap336 in proton transfer for deamination of isoxanthopterin. As hydrogen bonds between the substrate and surrounding residues play a key role in nucleophilic attack, we suggested mutating Thr195 to glutamic acid, which could enhance the hydrogen bonds and help isoxanthopterin get close to the active site. The simulations which change the substrate to pterin 6-carboxylate also performed for comparison. Our results provide reference for understanding of the mechanism of deaminase and for enhancing the deamination rate of isoxanthopterin deaminase.

scholarly journals Site-selective Protonation of the One-electron Reduced Cofactor in [FeFe]-Hydrogenase

2020 ◽  
Author(s):  
Konstantin Laun ◽  
Iuliia Baranova ◽  
Jifu Duan ◽  
Leonie Kertess ◽  
Florian Wittkamp ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Active Site ◽  
Catalytic Mechanism ◽  
Ph Dependence ◽  
H2 Evolution ◽  
Proton Reduction ◽  
Ph Values ◽  
Site Selective ◽  
H2 Oxidation ◽  
Diiron Site

Hydrogenases are microbial redox enzymes that catalyze H2 oxidation and proton reduction (H2 evolution). While all hydrogenases show high oxidation activities, the majority of [FeFe]-hydrogenases are excellent H2 evolution catalysts as well. Their active site cofactor comprises a [4Fe-4S] cluster covalently linked to a diiron site equipped with carbon monoxide and cyanide ligands that facilitate catalysis at low overpotential. Distinct proton transfer pathways connect the active site niche with the solvent, resulting in a non-trivial dependence of hydrogen turnover and bulk pH. To analyze the catalytic mechanism of [FeFe]-hydrogenase, we employ in situ infrared spectroscopy and infrared spectro-electrochemistry. Titrating the pH under H2 oxidation or H2 evolution conditions reveals the influence of site-selective protonation on the equilibrium of reduced cofactor states. Governed by pKa differences across the active site niche and proton transfer pathways, we find that individual electrons are stabilized either at the [4Fe-4S] cluster (alkaline pH values) or at the diiron site (acidic pH values). This observation is discussed in the context of the natural pH dependence of hydrogen turnover as catalyzed by [FeFe]-hydrogenase.<br>

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