scholarly journals Unexpected electron spin density on the axial methionine ligand in CuA suggests its involvement in electron pathways

2020 ◽  
Vol 56 (8) ◽  
pp. 1223-1226
Author(s):  
Marcos N. Morgada ◽  
María-Eugenia Llases ◽  
Estefanía Giannini ◽  
María-Ana Castro ◽  
Pedro M. Alzari ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electronic Structure ◽  
Spin Density ◽  
Electron Spin ◽  
Unpaired Electron ◽  
Axial Ligand ◽  
Electron Spin Density ◽  
Metal Site ◽  
Electron Transfer Pathways

The presence of unpaired electron spin density in the axial ligand of the CuA site suggest a new description of the electronic structure of this metal site that supports the feasibility of previously neglected electron transfer pathways.

scholarly journals Unexpected Electron Spin Density on the Axial Methionine Ligand in CuA Suggests Its Involvement in Electron Pathways

2019 ◽  
Author(s):  
Marcos N. Morgada ◽  
María-Eugenia Llases ◽  
Estefania Giannini ◽  
María Ana Castro ◽  
Pedro M. Alzari ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Spin Density ◽  
Electron Spin ◽  
Theoretical Calculations ◽  
Metal Center ◽  
Cellular Respiration ◽  
Electron Spin Density ◽  
Dioxygen Reduction ◽  
Nmr Study ◽  
Electron Transfer Pathways

<p>The Cu<sub>A</sub> center is a paradigm for the study of long-range biological electron transfer. This metal center is an essential cofactor for terminal oxidases like Cytochrome <i>c</i> oxidase, the enzymatic complex responsible for cellular respiration in eukaryotes and in most bacteria. Cu<sub>A</sub> acts as an electron hub by transferring electrons from reduced cytochrome <i>c</i> to the catalytic site of the enzyme where dioxygen reduction takes place. Different electron transfer pathways have been proposed involving a weak axial methionine ligand residue, conserved in all Cu<sub>A</sub> sites. This hypothesis has been challenged by theoretical calculations indicating the lack of electron spin density in this ligand. Here we report an NMR study with selectively labeled methionine in a native Cu<sub>A</sub>. NMR spectroscopy discloses the presence of net electron spin density in the methionine axial ligand in the two alternative ground states of this metal center. Similar spin delocalization observed on two second sphere mutants further supports this evidence. These data provide a novel view of the electronic structure of Cu<sub>A</sub> centers and support previously neglected electron transfer pathways. </p>

scholarly journals Unexpected Electron Spin Density on the Axial Methionine Ligand in CuA Suggests Its Involvement in Electron Pathways

2019 ◽  
Author(s):  
Marcos N. Morgada ◽  
María-Eugenia Llases ◽  
Estefania Giannini ◽  
María Ana Castro ◽  
Pedro M. Alzari ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Spin Density ◽  
Electron Spin ◽  
Theoretical Calculations ◽  
Metal Center ◽  
Cellular Respiration ◽  
Electron Spin Density ◽  
Dioxygen Reduction ◽  
Nmr Study ◽  
Electron Transfer Pathways

<p>The Cu<sub>A</sub> center is a paradigm for the study of long-range biological electron transfer. This metal center is an essential cofactor for terminal oxidases like Cytochrome <i>c</i> oxidase, the enzymatic complex responsible for cellular respiration in eukaryotes and in most bacteria. Cu<sub>A</sub> acts as an electron hub by transferring electrons from reduced cytochrome <i>c</i> to the catalytic site of the enzyme where dioxygen reduction takes place. Different electron transfer pathways have been proposed involving a weak axial methionine ligand residue, conserved in all Cu<sub>A</sub> sites. This hypothesis has been challenged by theoretical calculations indicating the lack of electron spin density in this ligand. Here we report an NMR study with selectively labeled methionine in a native Cu<sub>A</sub>. NMR spectroscopy discloses the presence of net electron spin density in the methionine axial ligand in the two alternative ground states of this metal center. Similar spin delocalization observed on two second sphere mutants further supports this evidence. These data provide a novel view of the electronic structure of Cu<sub>A</sub> centers and support previously neglected electron transfer pathways. </p>

Unpaired Electron Spin Density Distribution across Reduced [2Fe-2S] Cluster Ligands by 13Cβ-Cysteine Labeling

2017 ◽  
Vol 57 (2) ◽  
pp. 741-746 ◽  
Author(s):  
Alexander T. Taguchi ◽  
Yoshiharu Miyajima-Nakano ◽  
Risako Fukazawa ◽  
Myat T. Lin ◽  
Amgalanbaatar Baldansuren ◽  
...  
Keyword(s):  
Density Distribution ◽  
Spin Density ◽  
Electron Spin ◽  
Unpaired Electron ◽  
Spin Density Distribution ◽  
Electron Spin Density ◽  
Cysteine Labeling

Theoretical Analysis of the Electron Spin Density Distribution of the Flavin Semiquinone Isoalloxazine Ring within Model Protein Environments

2002 ◽  
Vol 106 (18) ◽  
pp. 4729-4735 ◽  
Author(s):  
José I. García ◽  
Milagros Medina ◽  
Javier Sancho ◽  
Pablo J. Alonso ◽  
Carlos Gómez-Moreno ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Density Distribution ◽  
Spin Density ◽  
Electron Spin ◽  
Spin Density Distribution ◽  
Electron Spin Density ◽  
Model Protein

Alkali-metal electron spin density shift induced by a helium nanodroplet

2010 ◽  
Vol 108 (7-9) ◽  
pp. 1005-1011 ◽  
Author(s):  
Markus Koch ◽  
Carlo Callegari ◽  
Wolfgang E. Ernst
Keyword(s):  
Alkali Metal ◽  
Spin Density ◽  
Electron Spin ◽  
Electron Spin Density ◽  
Density Shift ◽  
Metal Electron

Electron Spin Density on the N-Donor Atoms of Cu(II)–(Bis)oxamidato Complexes As Probed by a Pulse ELDOR Detected NMR

2015 ◽  
Vol 119 (43) ◽  
pp. 13762-13770 ◽  
Author(s):  
Azar Aliabadi ◽  
Ruslan Zaripov ◽  
Kev Salikhov ◽  
Violeta Voronkova ◽  
Evgeniya Vavilova ◽  
...  
Keyword(s):  
Spin Density ◽  
Electron Spin ◽  
Electron Spin Density ◽  
Oxamidato Complexes
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