Journal of Bioenergetics and Biomembranes

, Volume 31, Issue 3, pp 191–200

Structural Basis of Multifunctional Bovine Mitochondrial Cytochrome bc1 Complex

Authors

  • Chang-An Yu
    • Department of Biochemistry and Molecular BiologyOklahoma State University
  • Hua Tian
    • Department of Biochemistry and Molecular BiologyOklahoma State University
  • Li Zhang
    • Department of Biochemistry and Molecular BiologyOklahoma State University
  • Kai-Ping Deng
    • Department of Biochemistry and Molecular BiologyOklahoma State University
  • Sudha K. Shenoy
    • Department of Biochemistry and Molecular BiologyOklahoma State University
  • Linda Yu
    • Department of Biochemistry and Molecular BiologyOklahoma State University
  • Di Xia
    • The Howard Hughes Medical Institute and Department of BiochemistryUniversity of Texas Southwestern Medical Center
  • Hoeon Kim
    • The Howard Hughes Medical Institute and Department of BiochemistryUniversity of Texas Southwestern Medical Center
  • Johann Deisenhofer
    • The Howard Hughes Medical Institute and Department of BiochemistryUniversity of Texas Southwestern Medical Center
Article

DOI: 10.1023/A:1005411510913

Cite this article as:
Yu, C., Tian, H., Zhang, L. et al. J Bioenerg Biomembr (1999) 31: 191. doi:10.1023/A:1005411510913

Abstract

The mitochondrial cytochrome bc1 complex is a multifunctional membrane protein complex. Itcatalyzes electron transfer, proton translocation, peptide processing, and superoxide generation.Crystal structure data at 2.9 Å resolution not only establishes the location of the redox centersand inhibitor binding sites, but also suggests a movement of the head domain of the iron–sulfurprotein (ISP) during bc1 catalysis and inhibition of peptide-processing activity during complexmaturation. The functional importance of the movement of extramembrane (head) domain ofISP in the bc1 complex is confirmed by analysis of the Rhodobacter sphaeroides bc1 complexmutants with increased rigidity in the ISP neck and by the determination of rate constants foracid/base-induced intramolecular electron transfer between [2Fe–2S] and heme c1 in nativeand inhibitor-loaded beef complexes. The peptide-processing activity is activated in bovineheart mitochondrial bc1 complex by nonionic detergent at concentrations that inactivate electrontransfer activity. This peptide-processing activity is shown to be associated with subunits Iand II by cloning, overexpression and in vitro reconstitution. The superoxide-generation siteof the cytochrome bc1 complex is located at reduced bL and Q•−. The reaction is membranepotential-, and cytochrome c-dependent.

cytochrome bc1 complexelectron transfer reaction: mitochondrial-processing peptidasesuperoxide-generation activityelectron transfer inhibitors
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Copyright information

© Plenum Publishing Corporation 1999