Related Experiment Video
Updated: Sep 4, 2025
06:31
Preparation of SNS CobaltII Pincer Model Complexes of Liver Alcohol Dehydrogenase
Published on: March 19, 2020
7.2K
Single crystal spectroscopy and multiple structures from one crystal (MSOX) define catalysis in copper nitrite
Samuel L Rose1, Seiki Baba2, Hideo Okumura2
1Molecular Biophysics Group, Life Sciences Building, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom.
Summary
This study reveals that electron transfer in a copper nitrite reductase (CuNiR) is gated, significantly hindering its activity. Understanding this gating mechanism is crucial for developing more efficient metalloproteins.
Area of Science:
- Biochemistry
- Biophysics
- Enzymology
Background:
- Enzymes use redox-coupled centers for catalysis, requiring precise electron transfer (ET) regulation.
- Copper nitrite reductases (CuNiRs) are model systems for studying proton-coupled ET and substrate binding.
- A two-domain CuNiR (Br2DNiR) exhibits low activity, with its active site occupied by water molecules.
Purpose of the Study:
- To investigate the gating mechanism of inter-copper ET in Br2DNiR.
- To understand the role of substrate binding in regulating enzymatic activity.
- To elucidate the reasons for the low catalytic efficiency of this specific CuNiR.
Main Methods:
- Single crystal spectroscopy and MSOX (multiple structures from one crystal) were used on as-isolated and nitrite-soaked crystals.
- Laser-flash photolysis and optical spectroscopy were employed to study electron transfer dynamics.
- Analysis of serial structures from MSOX movies provided insights into reaction intermediates.
Main Results:
- Inter-copper ET within the T1Cu-T2Cu redox system in Br2DNiR is heavily gated.
- Rapid ET from NADH to T1Cu occurs, but inter-Cu ET is minimal without nitrite.
- Incomplete reoxidation of T1Cu (approx. 20%) and slow NO formation were observed in the presence of nitrite.
Conclusions:
- The gating of inter-copper ET and slow NO formation are responsible for the low activity of Br2DNiR.
- This research provides insights into the regulation of redox reactions in metalloproteins.
- The findings are relevant for studying a broad range of biological redox systems.
![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
Related Concept Videos
02:50Catalysis
27.4K
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
27.4K
01:13Introduction to Mechanisms of Enzyme Catalysis
8.6K
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes...
8.6K
00:49Ligand Binding and Linkage
4.9K
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence...
4.9K
02:34Structural Isomerism
19.6K
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...
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...
19.6K
02:58Crystal Field Theory - Octahedral Complexes
27.3K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
27.3K
02:15Protein and Protein Structure
80.7K
Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective. They may serve in transport, storage, or membranes; or they may be toxins or enzymes. Their structures, like their functions, vary greatly. They are all, however, amino acid polymers arranged in a linear sequence.
A protein's shape is critical to its function. For example, an enzyme...
A protein's shape is critical to its function. For example, an enzyme...
80.7K