Related Experiment Video
Updated: Jan 31, 2026
07:59
Preparation of Nucleosome Core Particles Complexed with DNA Repair Factors for Cryo-Electron Microscopy Structural Determination
Published on: August 17, 2022
2.3K
Structural adaptations of photosynthetic complex I enable ferredoxin-dependent electron transfer
Jan M Schuller1, James A Birrell2, Hideaki Tanaka3,4
1Department of Structural Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. janschu@biochem.mpg.de gkurisu@protein.osaka-u.ac.jp marc.m.nowaczyk@rub.de.
Science (New York, N.Y.)
|December 22, 2018
Summary
Photosynthetic complex I uses ferredoxin to transfer electrons during cyclic electron flow, a key process in photosynthesis. This study reveals the structure and ferredoxin interaction mechanism of this vital complex.
Area of Science:
- Biochemistry
- Structural Biology
- Photosynthesis Research
Background:
- Photosynthetic complex I is crucial for cyclic electron flow (CEF) around photosystem I (PSI).
- CEF regulates photosynthetic energy conversion in organisms like cyanobacteria.
- Understanding the structural basis of CEF is vital for optimizing photosynthesis.
Purpose of the Study:
- To determine the high-resolution cryo-electron microscopy structure of photosynthetic complex I.
- To elucidate the mechanism of electron transfer from ferredoxin to complex I.
- To identify the key protein components involved in ferredoxin recognition.
Main Methods:
- Cryo-electron microscopy (cryo-EM) at 3.3-angstrom resolution.
- Structural analysis of photosynthetic complex I from *Thermosynechococcus elongatus*.
- In vitro reconstitution assays to mimic cyclic electron flow.
Main Results:
- A detailed structural model of photosynthetic complex I was obtained.
- Structural adaptations facilitating ferredoxin binding and electron transfer were identified.
- Ferredoxin was confirmed as the direct electron mediator between PSI and complex I, bypassing NADPH.
- The NdhS subunit was identified as critical for efficient ferredoxin association.
Conclusions:
- The structure provides mechanistic insights into ferredoxin-mediated electron transfer in CEF.
- NdhS plays a pivotal role in the recognition and efficient binding of ferredoxin to complex I.
- This work clarifies a fundamental aspect of photosynthetic energy regulation.
More Related Videos
Related Concept Videos
02:48Ionic Bonding and Electron Transfer
49.1K
Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence shell, and an anion (a negative ion) forms when a neutral atom gains one or more electrons in its valence shell. Compounds composed of ions are called ionic compounds (or salts), and their constituent ions are held together by ionic bonds: electrostatic forces of attraction between oppositely charged cations and anions.
49.1K
02:28Electronic Structure of Atoms
28.7K
An atom comprises protons and neutrons, which are contained inside the dense, central core called the nucleus, with electrons present around the nucleus. Taking into account the wave–particle duality of electrons and the uncertainty in position around the nucleus, quantum mechanics provides a more accurate model for the atomic structure. It describes atomic orbitals as the regions around the nucleus where electrons of discrete energy exist, characterized by four quantum...
28.7K
01:46Electron Transport Chain: Complex I and II
19.0K
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...
19.0K
01:32Assembly of Complex Microtubule Structures
2.5K
Complex microtubule structures are present in resting cells and in dividing cells. In resting cells, they are responsible for maintaining the cellular architecture, tracks for intracellular transport, positioning of organelles, assembly of cilia and flagella. They mediate the bipolar spindle assembly for chromosomal segregation and positioning of the cell division plate in dividing cells. The formation of microtubule complex structures depends on the cell type, cell stage, and cell function.
2.5K
01:07Radicals: Electronic Structure and Geometry
5.1K
This lesson delves into the geometry of a radical, which is influenced by the electronic structure of the molecule. The principle is similar to that of a lone pair, where the unpaired electron influences the geometry at the radical center.
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
5.1K
02:34Structural Isomerism
21.7K
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...
21.7K