Related Experiment Video

Updated: Jun 16, 2026

A New Approach for the Comparative Analysis of Multiprotein Complexes Based on 15N Metabolic Labeling and Quantitative Mass Spectrometry
08:04

A New Approach for the Comparative Analysis of Multiprotein Complexes Based on 15N Metabolic Labeling and Quantitative Mass Spectrometry

Published on: March 13, 2014

Heliobacterial Rieske/cytb complex

F Baymann1, W Nitschke

  • 1BIP, Centre National de la Recherche Scientifique, UPR9036, IFR88, 31 Chemin Joseph Aiguier, Marseille, France. baymann@ifr88.cnrs-mrs.fr.

Photosynthesis Research
|January 22, 2010
PubMed

Insights

The Heliobacteria Rieske/cytochrome b complex shares similarities with the b6f complex, featuring unique cofactor content and redox potentials. Its role in cyclic electron transfer is crucial for photosynthesis.

Area of Science:

  • Biochemistry
  • Photosynthesis research
  • Microbial metabolism

Background:

  • Rieske/cytochrome b complex structure and function in Heliobacteria are poorly understood.
  • Heliobacteria's phylogenetic position suggests a relationship to the b6f complex.
  • The complex includes a diheme cytochrome c, Rieske iron-sulfur protein, and transmembrane cytochrome b.

Purpose of the Study:

  • To elucidate the structure and function of the Heliobacteria Rieske/cytochrome b complex.
  • To compare its properties with the well-characterized b6f complex.
  • To understand its role in photosynthetic electron transfer.

Main Methods:

  • Phylogenetic analysis to infer structural relationships.
  • Spectroscopic methods to determine cofactor content and redox potentials.
  • Biochemical assays to investigate enzyme activity.

Main Results:

  • The Heliobacteria complex contains heme c(i) in the Q(i) binding pocket, similar to b6f complexes.
  • Redox midpoint potentials are more negative than in b6f complexes, aligning with its reaction partners.
  • The enzyme participates in cyclic electron transfer around Photosystem I (RCI).

Conclusions:

  • The Heliobacteria Rieske/cytochrome b complex is structurally and functionally related to the b6f complex.
  • Its unique cofactor and redox properties are adapted to its specific photosynthetic environment.
  • Despite challenges like oxygen sensitivity, functional studies are feasible and informative.

More Related Videos

From Constructs to Crystals – Towards Structure Determination of β-barrel Outer Membrane Proteins09:55

From Constructs to Crystals – Towards Structure Determination of β-barrel Outer Membrane Proteins

Published on: July 4, 2016

Rapid Isolation of the Mitoribosome from HEK Cells09:33

Rapid Isolation of the Mitoribosome from HEK Cells

Published on: October 4, 2018

Related Concept Videos

Electron Transport Chain: Complex III and IV01:43

Electron 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...
Electron Transport Chain: Complex I and II01:46

Electron 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...
The Supercomplexes in the Crista Membrane01:41

The 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...
Export of Misfolded Proteins out of the ER01:32

Export of Misfolded Proteins out of the ER

After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
Anoxygenic Phototrophic Bacteria01:28

Anoxygenic Phototrophic Bacteria

Anoxygenic phototrophic bacteria are a diverse group of microorganisms that perform photosynthesis without producing oxygen. They primarily include purple sulfur bacteria, purple nonsulfur bacteria, green sulfur bacteria, and green nonsulfur bacteria. These bacteria are classified into the Gammaproteobacteria, Alphaproteobacteria, Betaproteobacteria, Chlorobi, and Chloroflexi lineages, each with distinct physiological and ecological adaptations.Purple sulfur bacteria belong to the...
Electron Transport Chains01:28

Electron Transport Chains

The final stage of cellular respiration is oxidative phosphorylation that consists of two steps: the electron transport chain and chemiosmosis. The electron transport chain is a set of proteins found in the inner mitochondrial membrane in eukaryotic cells. Its primary function is to establish a proton gradient that can be used during chemiosmosis to produce ATP and generate electron carriers, such as NAD+ and FAD, that are used in glycolysis and the citric acid cycle.
The ETC is comprised of...