Related Experiment Video
Updated: Jun 12, 2026
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
10:01
Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
Published on: December 4, 2017
Versatile methodology toward NiN(2)S(2) complexes as nickel superoxide dismutase models: structure and proton
Eric M Gale1, Ashis K Patra, Todd C Harrop
1Department of Chemistry, University of Georgia, 1001 Cedar St, Athens, Georgia 30602, USA.
Inorganic Chemistry
|May 29, 2010
Summary
Researchers modeled nickel superoxide dismutase (Ni-SOD) active sites using novel NiN(2)S(2) complexes. These complexes reveal the exogenous thiolato-S may act as a proton acceptor, crucial for Ni-SOD
Area of Science:
- Bioinorganic Chemistry
- Coordination Chemistry
- Enzymology
Background:
- Nickel superoxide dismutase (Ni-SOD) is vital for cellular defense against reactive oxygen species.
- Understanding the Ni-SOD active site's structural and functional properties is key to its catalytic mechanism.
Purpose of the Study:
- To model the reduced active site of nickel superoxide dismutase (Ni-SOD).
- To investigate the role of exogenous thiolato-sulfur in Ni-SOD's catalytic cycle.
Main Methods:
- Synthesis of asymmetric NiN(2)S(2) complexes via S,S-bridge splitting of a dimeric metallosynthon.
- Electrochemical analysis to determine oxidation potentials relevant to SOD activity.
Main Results:
- Asymmetric NiN(2)S(2) complexes, (Et(4)N)[Ni(nmp)(SR)], were successfully synthesized.
- Complexes exhibited irreversible oxidation potentials within the SOD activity window.
- The exogenous thiolato-sulfur atom was identified as a potential proton acceptor.
Conclusions:
- The synthesized NiN(2)S(2) complexes effectively model the reduced Ni-SOD active site.
- The exogenous thiolato-S suggests a role in proton storage between SOD half-reactions, potentially involving Cys6 in native Ni-SOD.
Related Concept Videos
01:43Electron Transport Chain: Complex III and IV
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
01:41The Supercomplexes in the Crista Membrane
The mitochondrial cristae membrane is the primary site for the oxidative phosphorylation (OXPHOS) process of energy conversion mediated through respiratory complexes I to V. These complexes have been widely studied for decades, and it has been proven that they form supramolecular structures called respiratory supercomplexes (SC). These higher-order complexes may be crucial in maintaining the biochemical structure and improving the physiological activity of the individual complexes while...
01:46Electron Transport Chain: Complex I and II
The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce cytotoxic reactive oxygen species (ROS) due to the large electron flow during oxidative phosphorylation. While Complex I is one of the primary sources of superoxide radicals, ROS production by Complex II is uncommon and may only be observed in cancer cells with mutated complexes.
ROS generation is regulated and maintained at moderate levels necessary...
ROS generation is regulated and maintained at moderate levels necessary...
02:34Structural Isomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
02:51Metal-Ligand Bonds
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...