1. A 3.3 Å‐Resolution Structure of Hyperthermophilic Respiratory Complex III Reveals the Mechanism of Its Thermal Stability
- Author
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Xiaoyun Pang, Guohong Peng, Nina Morgner, Guoliang Zhu, Hartmut Michel, Yun Zhu, Jana Juli, Hui Zeng, Jan Hoffmann, Fei Sun, Shuangbo Zhang, and Yan Zhang
- Subjects
Models, Molecular ,Protein Structures ,Respiratory chain ,protein–protein interactions ,010402 general chemistry ,enzyme catalysis ,01 natural sciences ,Catalysis ,Protein–protein interaction ,Electron Transport ,03 medical and health sciences ,Protein structure ,Humans ,hyperthermophilic species ,Amino Acid Sequence ,Research Articles ,cytochrome bc1 complex ,030304 developmental biology ,0303 health sciences ,Aquifex aeolicus ,biology ,010405 organic chemistry ,Chemistry ,Thermophile ,General Medicine ,General Chemistry ,biology.organism_classification ,Transmembrane protein ,0104 chemical sciences ,3. Good health ,Transmembrane domain ,Coenzyme Q – cytochrome c reductase ,Biophysics ,Research Article - Abstract
Respiratory chain complexes convert energy by coupling electron flow to transmembrane proton translocation. Owing to a lack of atomic structures of cytochrome bc 1 complex (Complex III) from thermophilic bacteria, little is known about the adaptations of this macromolecular machine to hyperthermophilic environments. In this study, we purified the cytochrome bc1 complex of Aquifex aeolicus, one of the most extreme thermophilic bacteria known, and determined its structure with and without an inhibitor at 3.3 Å resolution. Several residues unique for thermophilic bacteria were detected that provide additional stabilization for the structure. An extra transmembrane helix at the N‐terminus of cyt. c 1 was found to greatly enhance the interaction between cyt. b and cyt. c 1, and to bind a phospholipid molecule to stabilize the complex in the membrane. These results provide the structural basis for the hyperstability of the cytochrome bc1 complex in an extreme thermal environment., A hot take on thermophiles: The hyperstability of respiratory complex III from Aquifex aeolicus provides a suitable environment for the internal electron transfer reaction at high temperature.
- Published
- 2019