Abstract
Mitochondrial cytochrome bc1 complex performs two functions: It is a respiratory multienzyme complex and it recognizes a mitochondrial targeting presequence. Refined crystal structures of the 11-subunit bc1 complex from bovine heart reveal full views of this bifunctional enzyme. The "Rieske" iron-sulfur protein subunit shows significant conformational changes in different crystal forms, suggesting a new electron transport mechanism of the enzyme. The mitochondrial targeting presequence of the "Rieske" protein (subunit 9) is lodged between the two "core" subunits at the matrix side of the complex. These "core" subunits are related to the matrix processing peptidase, and the structure unveils how mitochondrial targeting presequences are recognized.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Binding Sites
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Cattle
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Crystallization
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Crystallography, X-Ray
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Cytochrome b Group / chemistry
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Cytochrome b Group / metabolism
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Cytochromes c1 / chemistry
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Cytochromes c1 / metabolism
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Electron Transport
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Electron Transport Complex III / chemistry*
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Electron Transport Complex III / metabolism
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Enzyme Inhibitors / metabolism
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Hydrogen Bonding
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Hydroquinones / metabolism
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Intracellular Membranes / enzymology
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Iron-Sulfur Proteins / chemistry
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Iron-Sulfur Proteins / metabolism
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Methacrylates
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Mitochondria, Heart / enzymology*
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Models, Molecular
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Molecular Sequence Data
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Oxidation-Reduction
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Protein Conformation*
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Protein Structure, Secondary
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Thiazoles / metabolism
Substances
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Cytochrome b Group
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Enzyme Inhibitors
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Hydroquinones
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Iron-Sulfur Proteins
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Methacrylates
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Rieske iron-sulfur protein
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Thiazoles
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myxothiazol
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Cytochromes c1
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Electron Transport Complex III
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hydroquinone