A novel electron transfer mechanism suggested by crystallographic studies of mitochondrial cytochrome bc1 complex

Di Xia, Hoeon Kim, Chang An Yu, Linda Yu, Anatoly Kachurin, Li Zhang, Johann Deisenhofer

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The crystal structure of bovine mitochondrial cytochrome bc1 complex, an integral membrane protein complex of 11 different subunits with a total molecular mass of 242 kDa, demonstrated a tightly associated dimer consisting of three major regions: a matrix region primarily made of subunits core1, core2, 6, and 9; a transmembrane-helix region of 26 helices in the dimer contributed by cytochrome b, cytochrome c1, the Rieske iron-sulfur protein (ISP), subunits 7, 10, and 11; and an intermembrane-space region composed of extramembrane domains of ISP, cytochrome c1, and subunit 8. The structure also revealed the positions of and distances between irons of prosthetic groups, and two symmetry related cavities in the transmembrane-helix region upon dimerization of the bc1 complex. Extensive crystallographic studies on crystals of bc1 complexed with inhibitors of electron transfer identified binding pockets for both Q(o) and Q(i) site inhibitors. Discrete binding sites for subtypes of Q(o) site inhibitors have been mapped onto the Q(o) binding pocket, and bindings of different subtypes of Q(o) site inhibitors are capable of inducing dramatic conformational changes in the extramembrane domain of ISP. A novel electron transfer mechanism for the bc1 complex consistent with crystallographic observations is discussed.

Original languageEnglish (US)
Pages (from-to)673-679
Number of pages7
JournalBiochemistry and Cell Biology
Volume76
Issue number5
DOIs
StatePublished - 1998

Fingerprint

Cytochromes c1
Iron-Sulfur Proteins
Electron Transport Complex III
Dimers
Electrons
Cytochromes b
Dimerization
Protein Subunits
Molecular mass
Prosthetics
Membrane Proteins
Crystal structure
Binding Sites
Iron
Crystals
Rieske iron-sulfur protein

Keywords

  • bc1 complex
  • Conformational change
  • Electron transfer
  • Inhibitor
  • Structure

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Cell Biology

Cite this

A novel electron transfer mechanism suggested by crystallographic studies of mitochondrial cytochrome bc1 complex. / Xia, Di; Kim, Hoeon; Yu, Chang An; Yu, Linda; Kachurin, Anatoly; Zhang, Li; Deisenhofer, Johann.

In: Biochemistry and Cell Biology, Vol. 76, No. 5, 1998, p. 673-679.

Research output: Contribution to journalArticle

Xia, Di ; Kim, Hoeon ; Yu, Chang An ; Yu, Linda ; Kachurin, Anatoly ; Zhang, Li ; Deisenhofer, Johann. / A novel electron transfer mechanism suggested by crystallographic studies of mitochondrial cytochrome bc1 complex. In: Biochemistry and Cell Biology. 1998 ; Vol. 76, No. 5. pp. 673-679.
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AU - Deisenhofer, Johann

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