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Title: Mutational analysis of the Qi-site proton pathway in yeast cytochrome bc1 complex

Journal Article · · Biochemical and Biophysical Research Communications
 [1];  [2];  [3];  [4];  [5];  [3]
  1. Henan University (China); OSTI
  2. Henan University (China)
  3. Univ. Paris-Saclay, Gif-sur-Yvette (France)
  4. Univ. of Nottingham (United Kingdom)
  5. Michigan State Univ., East Lansing, MI (United States)
+ Show Author Affiliations

The respiratory cytochrome bc1 complex functions as a protonmotive ubiquinol:cytochrome c oxidoreductase. Lysine 228 (K228) located within the quinol reduction (Qi) site of the bc1 complex, has been reported as a key residue for proton transfer during the redox chemistry cycle to substrate quinone at Qi. In yeast, while single mutations had no effect, the combination of K228L and F225L resulted in a severe respiratory growth defect and inhibition of O2 consumption in intact cells. The inhibition was overcome by uncoupling the mitochondrial membrane or by suppressor mutations in the region of K228L-F225L. We suggest that the K228L mutation introduces energetic (and kinetic) barriers into normal electron- and proton transfer chemistry at Qi, which are relieved by dissipation of the opposing protonmotive force or through the restoration of favourable intraprotein proton transfer networks via suppressor mutation.

Research Organization:
Michigan State University, East Lansing, MI (United States)
Sponsoring Organization:
USDOE; USDOE Office of Science (SC)
Grant/Contract Number:
FG02-91ER20021
OSTI ID:
1800725
Journal Information:
Biochemical and Biophysical Research Communications, Journal Name: Biochemical and Biophysical Research Communications Journal Issue: 3 Vol. 523; ISSN 0006-291X
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (20)

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Characterization of mutations in the cytochrome b subunit of the bc1 complex of Rhodobacter sphaeroides that affect the quinone reductase site (Qc) journal April 1993
Specific roles of protein-phospholipid interactions in the yeast cytochrome bc1 complex structure journal December 2001
The antimalarial compound ELQ ‐400 is an unusual inhibitor of the bc 1 complex, targeting both Q o and Q i sites journal December 2017
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Protonmotive pathways and mechanisms in the cytochrome bc 1 complex journal May 2003
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Superoxide generation by complex III: From mechanistic rationales to functional consequences journal November 2013
Interplay between the hinge region of iron sulphur protein and the Qo site in the bc1 complex — Analysis of Plasmodium-like mutations in the yeast enzyme journal December 2015
Identifying involvement of Lys251/Asp252 pair in electron transfer and associated proton transfer at the quinone reduction site of Rhodobacter capsulatus cytochrome bc1 journal October 2016
Characterization of mutations in the cytochrome b subunit of the bc1 complex of Rhodobacter sphaeroides that affect the quinone reductase site (Qc) journal April 1993
Structural Basis for the Quinone Reduction in the bc 1 Complex:  A Comparative Analysis of Crystal Structures of Mitochondrial Cytochrome bc 1 with Bound Substrate and Inhibitors at the Q i Site † , ‡ journal August 2003
Mechanism of Ubiquinol Oxidation by the bc 1 Complex:  Different Domains of the Quinol Binding Pocket and Their Role in the Mechanism and Binding of Inhibitors † journal November 1999
Atomistic determinants of co-enzyme Q reduction at the Qi-site of the cytochrome bc1 complex journal September 2016
Human Disease-related Mutations in Cytochrome b Studied in Yeast journal January 2004
Specific roles of protein-phospholipid interactions in the yeast cytochrome bc1 complex structure journal December 2001
Recapitulation in Saccharomyces cerevisiae of Cytochrome b Mutations Conferring Resistance to Atovaquone in Pneumocystis jiroveci journal August 2003
The Cytochrome bc 1 Complex: Function in the Context of Structure journal March 2004

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Related Subjects

59 BASIC BIOLOGICAL SCIENCES
Biochemistry & Molecular Biology
Biophysics
Complex III catalytic activity
Mitochondrial mutations
Proton/electron transfer
Respiratory complex