Related Experiment Video
Updated: Sep 19, 2025
12:30
Structural Information from Single-molecule FRET Experiments Using the Fast Nano-positioning System
Published on: February 9, 2017
12.3K
The RNF/NQR redox pumps: a versatile system for energy transduction in bacteria and archaea
Wolfgang Buckel1, Ulrich Ermler2, Janet Vonck3
1Faculty of Biology, Philipps-Universität Marburg, Karl-von-Frisch-Straße 8, 35043, Marburg, Germany.
Applied Microbiology and Biotechnology
|June 17, 2025
Summary
Rhodobacter nitrogen fixation (RNF) complexes and NADH:quinone oxidoreductase (NQR) are crucial bacterial redox enzymes. Their shared mechanism involves conformational coupling for energy conversion, making them potential antibiotic targets.
Area of Science:
- Biochemistry
- Microbiology
- Structural Biology
Background:
- The Na+-translocating ferredoxin:NAD+ oxidoreductase (RNF) and NADH:quinone oxidoreductase (NQR) are vital membrane-bound enzyme complexes.
- RNF is essential for anaerobic metabolism in various bacteria, while NQR evolved from RNF and is found in diverse bacterial groups.
- Neither RNF nor NQR are related to eukaryotic respiratory complex I, highlighting their unique biological roles.
Purpose of the Study:
- To compare the putative reaction mechanisms of RNF and NQR redox pumps.
- To investigate the shared functional module of RNF and NQR complexes in redox-driven cation transport.
- To explore the potential of RNF and NQR as novel antibiotic targets.
Main Methods:
- Comparative analysis of RNF and NQR structures and functions.
- Review of recent 3D structural data for RNF and NQR.
- Examination of electron transfer and cation translocation mechanisms.
Main Results:
- RNF and NQR share a core complex of four subunits essential for cation transport.
- Recent structural studies reveal conformational coupling between electron transfer and Na+ translocation in RNF/NQR.
- A common principle of energy conversion based on conformational coupling is proposed for both enzyme systems.
Conclusions:
- RNF and NQR represent a distinct family of redox-driven proton/sodium pumps.
- The conformational coupling mechanism is central to the function of RNF and NQR.
- RNF and NQR are promising targets for the development of new antibiotics.
Keywords:
Electrochemical proton gradientElectrochemical sodium gradientElectron transportNQRRNFRespirationMore Related Videos
12:22Ratiometric Biosensors that Measure Mitochondrial Redox State and ATP in Living Yeast Cells
Published on: July 22, 2013
21.2K
05:06Author Spotlight: Advancing Antibiotic Resistance Research Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System
Published on: January 5, 2024
748
Related Concept Videos
01:27Redox Reactions
221
Redox reactions are vital biochemical processes that underpin energy metabolism in cells. These reactions involve the transfer of electrons between molecules, occurring in tandem as oxidation and reduction. Oxidation refers to the loss of electrons, while reduction denotes their gain. This coupling ensures the seamless flow of electrons through metabolic pathways. For example, in bacterial metabolism, glucose undergoes oxidation to carbon dioxide, while oxygen is simultaneously reduced to...
221
01:29Electron Transport Chain Components
238
The electron transport chain (ETC) is a crucial metabolic pathway that facilitates energy conversion in prokaryotic and eukaryotic cells. In eukaryotes, the ETC comprises four membrane-associated protein complexes in the inner mitochondrial membrane. In prokaryotes, the ETC in the plasma membrane can vary in composition, with fewer or different complexes depending on the organism and environmental conditions. These complexes transfer electrons from electron donors, such as NADH and FADH2, to...
238
01:30Anoxygenic Photosynthesis
180
Anoxygenic photosynthesis is a phototrophic process that captures light energy to drive carbon fixation without producing molecular oxygen. Unlike oxygenic photosynthesis, which utilizes water as an electron donor and releases oxygen, anoxygenic phototrophs use alternative electron donors such as hydrogen sulfide (H₂S), elemental sulfur (S⁰), or thiosulfate (S₂O₃²⁻). This process is carried out by diverse groups of bacteria, including purple bacteria, green...
180
01:29Role of Reduced Coenzymes NADH and FADH₂
12.7K
The energy released from the breakdown of the chemical bonds within nutrients can be stored either through the reduction of electron carriers or in the bonds of adenosine triphosphate (ATP). In living systems, a small class of compounds functions as mobile electron carriers, molecules that bind to and shuttle high-energy electrons between compounds in pathways. The principal electron carriers that will be considered originate from the B vitamin group and are derivatives of nucleotides; they are...
12.7K
01:15Metabolism of Chemolithotrophs
192
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation.
192
01:19Oxidation and Reduction of Organic Molecules
7.8K
Energy production within a cell involves many coordinated chemical pathways. Most of these pathways are combinations of oxidation and reduction reactions, which occur at the same time. An oxidation reaction strips an electron from an atom in a compound, and the addition of this electron to another compound is a reduction reaction. Because oxidation and reduction usually occur together, these pairs of reactions are called redox reactions.
The removal of an electron from a molecule, results in a...
The removal of an electron from a molecule, results in a...
7.8K