Synthetic and Structural Studies of Butterfly Fe/S/P Cluster Complexes Related to the Active Site of [FeFe]-Hydrogenases. Proton Reduction to H2Catalyzed by (η1-Ph2PS-η1)2Fe2(CO)6

2008 ◽  
Vol 27 (15) ◽  
pp. 3714-3721 ◽  
Author(s):  
Li-Cheng Song ◽  
Guang-Huai Zeng ◽  
Shao-Xia Lou ◽  
Hui-Ning Zan ◽  
Jiang-Bo Ming ◽  
...  
Keyword(s):  
Active Site ◽  
Structural Studies ◽  
Proton Reduction ◽  
Cluster Complexes

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>

Mutational and structural studies of the active-site residues in truncatedFibrobacter succinogenes1,3–1,4-β-D-glucanase

2008 ◽  
Vol 64 (12) ◽  
pp. 1259-1266 ◽  
Author(s):  
Li-Chu Tsai ◽  
Hsiao-Chuan Huang ◽  
Ching-Hua Hsiao ◽  
Yuan-Neng Chiang ◽  
Lie-Fen Shyur ◽  
...  
Keyword(s):  
Active Site ◽  
Structural Studies ◽  
Active Site Residues

RNA Splicing by the Spliceosome

2020 ◽  
Vol 89 (1) ◽  
pp. 359-388 ◽  
Author(s):  
Max E. Wilkinson ◽  
Clément Charenton ◽  
Kiyoshi Nagai
Keyword(s):  
Splice Site ◽  
Active Site ◽  
Rna Splicing ◽  
Messenger Rna ◽  
Structural Studies ◽  
U2 Snrna ◽  
U6 Snrna ◽  
Mature Mrna ◽  
Catalytic Metal ◽  
Small Nuclear Ribonucleoproteins

The spliceosome removes introns from messenger RNA precursors (pre-mRNA). Decades of biochemistry and genetics combined with recent structural studies of the spliceosome have produced a detailed view of the mechanism of splicing. In this review, we aim to make this mechanism understandable and provide several videos of the spliceosome in action to illustrate the intricate choreography of splicing. The U1 and U2 small nuclear ribonucleoproteins (snRNPs) mark an intron and recruit the U4/U6.U5 tri-snRNP. Transfer of the 5′ splice site (5′SS) from U1 to U6 snRNA triggers unwinding of U6 snRNA from U4 snRNA. U6 folds with U2 snRNA into an RNA-based active site that positions the 5′SS at two catalytic metal ions. The branch point (BP) adenosine attacks the 5′SS, producing a free 5′ exon. Removal of the BP adenosine from the active site allows the 3′SS to bind, so that the 5′ exon attacks the 3′SS to produce mature mRNA and an excised lariat intron.

Di-Iron Analogue of [FeFe]-Hydrogenase Active Site as a Molecular Electro-catalyst for Proton Reduction

2020 ◽  
Vol 150 (12) ◽  
pp. 3409-3414
Author(s):  
Xia Zhang ◽  
Lihong Liu ◽  
Weiming Cao ◽  
Dongjun Lv
Keyword(s):  
Active Site ◽  
Proton Reduction

Synthesis and Characterization of Single, Double, and Triple Butterfly [2Fe2E] (E = Se, S) Cluster Complexes Related to the Active Site of [FeFe]-Hydrogenases

2011 ◽  
Vol 30 (15) ◽  
pp. 4097-4107 ◽  
Author(s):  
Wei Gao ◽  
Li-Cheng Song ◽  
Bang-Shao Yin ◽  
Hui-Ning Zan ◽  
De-Fu Wang ◽  
...  
Keyword(s):  
Active Site ◽  
Synthesis And Characterization ◽  
Cluster Complexes

Active Site of Lysyl-tRNA Synthetase:  Structural Studies of the Adenylation Reaction†

Biochemistry ◽  
2000 ◽  
Vol 39 (29) ◽  
pp. 8418-8425 ◽  
Author(s):  
Gianluigi Desogus ◽  
Flavia Todone ◽  
Peter Brick ◽  
Silvia Onesti
Keyword(s):  
Active Site ◽  
Trna Synthetase ◽  
Structural Studies

scholarly journals Crystallization and preliminary X-ray diffraction analysis of human DNA primase

2014 ◽  
Vol 70 (2) ◽  
pp. 206-210 ◽  
Author(s):  
Andrey G. Baranovskiy ◽  
Jianyou Gu ◽  
Nigar D. Babayeva ◽  
Vinod B. Agarkar ◽  
Yoshiaki Suwa ◽  
...  
Keyword(s):  
Active Site ◽  
Large Subunit ◽  
Structural Studies ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Human Dna ◽  
Structural Details

Human primase synthesizes RNA primers and transfers them to the active site of Pol α with subsequent extension with dNTPs. Human primase is a heterodimer of two subunits: a small catalytic subunit (p49) and a large subunit (p58). The structural details of the initiation and elongation steps of primer synthesis, as well as primer length counting, are not known. To address these questions, structural studies of human primase were initiated. Two types of crystals were obtained. The best diffracting crystals belonged to space groupP1, with unit-cell parametersa= 86.2,b= 88.9,c= 94.68 Å, α = 93.82, β = 96.57, γ = 111.72°, and contained two heterodimers of full-length p49 and p59 subunits in the asymmetric unit.

Binuclear Iron−Sulfur Complexes with Bidentate Phosphine Ligands as Active Site Models of Fe-Hydrogenase and Their Catalytic Proton Reduction

2007 ◽  
Vol 46 (6) ◽  
pp. 1981-1991 ◽  
Author(s):  
Weiming Gao ◽  
Jesper Ekström ◽  
Jianhui Liu ◽  
Changneng Chen ◽  
Lars Eriksson ◽  
...  
Keyword(s):  
Active Site ◽  
Phosphine Ligands ◽  
Proton Reduction ◽  
Iron Sulfur ◽  
Bidentate Phosphine ◽  
Binuclear Iron
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