Structure of the alternative complex III in a supercomplex with cytochrome oxidase

Chang Sun, Samir Benlekbir, Padmaja Venkatakrishnan, Yuhang Wang, Sangjin Hong, Jonathan Hosler, Emad Tajkhorshid (), John L. Rubinstein () and Robert B. Gennis ()
Additional contact information
Chang Sun: University of Illinois
Samir Benlekbir: The Hospital for Sick Children Research Institute
Padmaja Venkatakrishnan: University of Illinois
Yuhang Wang: University of Illinois
Sangjin Hong: University of Illinois
Jonathan Hosler: University of Mississippi Medical Center
Emad Tajkhorshid: University of Illinois
John L. Rubinstein: The Hospital for Sick Children Research Institute
Robert B. Gennis: University of Illinois

Nature, 2018, vol. 557, issue 7703, 123-126

Abstract: Abstract Alternative complex III (ACIII) is a key component of the respiratory and/or photosynthetic electron transport chains of many bacteria1–3. Like complex III (also known as the bc1 complex), ACIII catalyses the oxidation of membrane-bound quinol and the reduction of cytochrome c or an equivalent electron carrier. However, the two complexes have no structural similarity4–7. Although ACIII has eluded structural characterization, several of its subunits are known to be homologous to members of the complex iron–sulfur molybdoenzyme (CISM) superfamily8, including the proton pump polysulfide reductase9,10. We isolated the ACIII from Flavobacterium johnsoniae with native lipids using styrene maleic acid copolymer11–14, both as an independent enzyme and as a functional 1:1 supercomplex with an aa3-type cytochrome c oxidase (cyt aa3). We determined the structure of ACIII to 3.4 Å resolution by cryo-electron microscopy and constructed an atomic model for its six subunits. The structure, which contains a [3Fe–4S] cluster, a [4Fe–4S] cluster and six haem c units, shows that ACIII uses known elements from other electron transport complexes arranged in a previously unknown manner. Modelling of the cyt aa3 component of the supercomplex revealed that it is structurally modified to facilitate association with ACIII, illustrating the importance of the supercomplex in this electron transport chain. The structure also resolves two of the subunits of ACIII that are anchored to the lipid bilayer with N-terminal triacylated cysteine residues, an important post-translational modification found in numerous prokaryotic membrane proteins that has not previously been observed structurally in a lipid bilayer.

Date: 2018
References: Add references at CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/s41586-018-0061-y Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:557:y:2018:i:7703:d:10.1038_s41586-018-0061-y

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/s41586-018-0061-y

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().