Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Electron Transport Chain: Complex III and IV01:43

Electron Transport Chain: Complex III and IV

9.4K
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...
9.4K
Electron Transport Chains01:28

Electron Transport Chains

114.1K
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...
114.1K
Electron Transport Chain: Complex I and II01:46

Electron Transport Chain: Complex I and II

19.2K
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...
19.2K
Oxygen Transport in the Blood01:27

Oxygen Transport in the Blood

7.4K
Hemoglobin (Hb) is a crucial molecule in the human body, consisting of four polypeptide chains, each bound to an iron-containing heme group. This unique structure enables hemoglobin to bind to oxygen, with each molecule capable of combining with four molecules of oxygen, leading to rapid and reversible oxygen loading. When fully loaded with oxygen, it is called oxyhemoglobin, while hemoglobin that has released oxygen is called reduced hemoglobin or deoxyhemoglobin. As hemoglobin binds oxygen,...
7.4K
Hemoglobin01:24

Hemoglobin

9.1K
Hemoglobin is a globular protein made up of four subunits. Two of these subunits are alpha chains, and the other two are beta chains. Each subunit contains a molecule of heme, which has an iron atom and can bind to oxygen. When an oxygen molecule binds to one heme group, it changes the shape of hemoglobin, making it easier for the other heme groups to bind oxygen as well.
When all four heme groups are bound to oxygen, the resulting molecule is called oxyhemoglobin. As a result, arterial blood...
9.1K
The Supercomplexes in the Crista Membrane01:41

The Supercomplexes in the Crista Membrane

3.1K
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...
3.1K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

A mononuclear nonheme iron complex with higher affinity for O<sub>2</sub> than CO via hydrogen bonding.

Nature communications·2026
Same author

Spontaneous Reduction of Cu(II) Complexes with Imidazole-Derived Ligands in Acetonitrile.

Molecules (Basel, Switzerland)·2026
Same author

Periodic Hirshfeld Atom Refinement.

The journal of physical chemistry letters·2026
Same author

Generation and Nitric Oxide Reactivity of a Cobalt(II) Superoxide Complex via Guanidine-Based Ligand Non-Innocence.

JACS Au·2025
Same author

Hydrogen-Producing Catalysts Based on Ferredoxin Scaffolds.

Advanced science (Weinheim, Baden-Wurttemberg, Germany)·2025
Same author

Tuning Reactivity in Cu/TEMPO Catalyzed Alcohol Oxidation Reactions.

Chemistry, an Asian journal·2025

Related Experiment Video

Updated: Feb 26, 2026

Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
10:01

Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase

Published on: December 4, 2017

12.8K

Effective intermediate-spin iron in O2-transporting heme proteins.

Nils Schuth1, Stefan Mebs1, Dennis Huwald2

  • 1Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany.

Proceedings of the National Academy of Sciences of the United States of America
|July 26, 2017
PubMed
Summary

This study reveals the electronic structure of iron-oxygen bonds in heme proteins like myoglobin and hemoglobin. It unifies classical models, showing a ferrous iron center and significant double-bond character for efficient oxygen transport.

Keywords:
O2 bindingX-ray spectroscopyheme cofactorquantum chemistryspin state

More Related Videos

Electrophoretic Mobility Shift Assay EMSA for the Study of RNA-Protein Interactions: The IRE/IRP Example
12:44

Electrophoretic Mobility Shift Assay EMSA for the Study of RNA-Protein Interactions: The IRE/IRP Example

Published on: December 3, 2014

55.0K
Measurement of Heme Synthesis Levels in Mammalian Cells
09:43

Measurement of Heme Synthesis Levels in Mammalian Cells

Published on: July 9, 2015

12.6K

Related Experiment Videos

Last Updated: Feb 26, 2026

Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
10:01

Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase

Published on: December 4, 2017

12.8K
Electrophoretic Mobility Shift Assay EMSA for the Study of RNA-Protein Interactions: The IRE/IRP Example
12:44

Electrophoretic Mobility Shift Assay EMSA for the Study of RNA-Protein Interactions: The IRE/IRP Example

Published on: December 3, 2014

55.0K
Measurement of Heme Synthesis Levels in Mammalian Cells
09:43

Measurement of Heme Synthesis Levels in Mammalian Cells

Published on: July 9, 2015

12.6K

Area of Science:

  • Biochemistry
  • Biophysics
  • Quantum Chemistry

Background:

  • Heme proteins are crucial for biological oxygen management.
  • The precise nature of the iron-oxygen bond in these proteins has been a long-standing debate.

Purpose of the Study:

  • To determine the molecular and electronic structures of heme sites in myoglobin and hemoglobin.
  • To elucidate the iron-oxygen bonding in oxygenated heme proteins.

Main Methods:

  • Energy-sampling and rapid-scan X-ray Kβ emission and K-edge absorption spectroscopy.
  • Quantum chemistry calculations, including density functional theory and complete-active-space self-consistent-field methods.
  • Analysis of unligated (deoxy), CO-inhibited (carboxy), and O2-bound (oxy) heme states in myoglobin and hemoglobin solutions and porphyrin compounds.

Main Results:

  • Identified high-spin Fe(II) in deoxy and low-spin Fe(II) in carboxy heme states.
  • Revealed an intermediate-spin iron center in oxy heme, with two unpaired Fe(d) spins.
  • Characterized the Fe-O2 bond as having ferrous iron, minor superoxide character, significant double-bond properties, and three-center electron delocalization.

Conclusions:

  • The study provides a unifying view of O2 bonding in heme proteins, reconciling conflicting classical models.
  • The described Fe-O2 bonding is optimized for reversible oxygen transport.
  • Findings contribute to understanding the fundamental mechanisms of oxygen management in biological systems.