Related Experiment Video
Updated: May 5, 2026

Visualization of ATP Synthase Dimers in Mitochondria by Electron Cryo-tomography
Published on: September 14, 2014
Crystal structure of mitochondrial respiratory membrane protein complex II
1Tsinghua-IBP Joint Research Group for Structural Biology, Tsinghua University, Beijing 100084, China.
Abstract:
The mitochondrial respiratory Complex II or succinate:ubiquinone oxidoreductase (SQR) is an integral membrane protein complex in both the tricarboxylic acid cycle and aerobic respiration. Here we report the first crystal structure of Complex II from porcine heart at 2.4 A resolution and its complex structure with inhibitors 3-nitropropionate and 2-thenoyltrifluoroacetone (TTFA) at 3.5 A resolution. Complex II is comprised of two hydrophilic proteins, flavoprotein (Fp) and iron-sulfur protein (Ip), and two transmembrane proteins (CybL and CybS), as well as prosthetic groups required for electron transfer from succinate to ubiquinone. The structure correlates the protein environments around prosthetic groups with their unique midpoint redox potentials. Two ubiquinone binding sites are discussed and elucidated by TTFA binding. The Complex II structure provides a bona fide model for study of the mitochondrial respiratory system and human mitochondrial diseases related to mutations in this complex.
More Related Videos
08:37Analyzing Supercomplexes of the Mitochondrial Electron Transport Chain with Native Electrophoresis, In-gel Assays, and Electroelution
Published on: June 1, 2017
08:07Analysis of the Expression and Complexes Assembly of the Mitochondrial Respiratory Chain Proteins in the Fission Yeast Schizosaccharomyces pombe
Published on: May 2, 2025
Related Concept Videos
Electron Transport Chains
The ETC is comprised of...
The Inner Mitochondrial Membrane
Electron Transport Chain: Complex I and II
ROS generation is regulated and maintained at moderate levels necessary...
The Supercomplexes in the Crista Membrane
ATP Synthase: Structure
Electron Transport Chain: Complex III and IV