2FYU: Crystal Structure Of Bovine Heart Mitochondrial Bc1 With Jg144 Inhibitor

Citation:
Abstract
In the cytochrome bc(1) complex, the swivel motion of the iron-sulfur protein (ISP) between two redox sites constitutes a key component of the mechanism that achieves the separation of the two electrons in a substrate molecule at the quinol oxidation (Q(o)) site. The question remaining is how the motion of ISP is controlled so that only one electron enters the thermodynamically favorable chain via ISP. An analysis of eight structures of mitochondrial bc(1) with bound Q(o) site inhibitors revealed that the presence of inhibitors causes a bidirectional repositioning of the cd1 helix in the cytochrome b subunit. As the cd1 helix forms a major part of the ISP binding crater, any positional shift of this helix modulates the ability of cytochrome b to bind ISP. The analysis also suggests a mechanism for reversal of the ISP fixation when the shape complementarity is significantly reduced after a positional reorientation of the reaction product quinone. The importance of shape complementarity in this mechanism was confirmed by functional studies of bc(1) mutants and by a structure determination of the bacterial form of bc(1). A mechanism for the high fidelity of the bifurcated electron transfer is proposed.
PDB ID: 2FYUDownload
MMDB ID: 40872
PDB Deposition Date: 2006/2/8
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.26  Å
Source Organism:
Similar Structures:
Biological Unit for 2FYU: 22-meric; determined by author and by software (PISA,PQS)
Molecular Components in 2FYU
Label Count Molecule
Proteins (22 molecules)
2
Ubiquinol-cytochrome-c Reductase Complex Core Protein I, Mitochondrial(Gene symbol: UQCRC1)
Molecule annotation
2
Ubiquinol-cytochrome-c Reductase Complex Core Protein 2, Mitochondrial(Gene symbol: UQCRC2)
Molecule annotation
2
Cytochrome B(Gene symbol: CYTB)
Molecule annotation
2
Cytochrome C1, Heme Protein, Mitochondrial(Gene symbol: CYC1)
Molecule annotation
2
Ubiquinol-cytochrome C Reductase Iron-sulfur Subunit, Mitochondrial(Gene symbol: UQCRFS1)
Molecule annotation
2
Hypothetical Protein Loc616871(Gene symbol: UQCRB)
Molecule annotation
2
Ubiquinol-cytochrome C Reductase Complex Ubiquinone-binding Protein Qp-c(Gene symbol: UQCRQ)
Molecule annotation
2
Ubiquinol-cytochrome C Reductase Complex 11 KDA Protein(Gene symbol: UQCRH)
Molecule annotation
2
Ubiquinol-cytochrome C Reductase Iron-sulfur Subunit, Mitochondrial(Gene symbol: UQCRFS1)
Molecule annotation
2
Ubiquinol-cytochrome C Reductase Complex 7.2 KDA Protein(Gene symbol: UQCR10)
Molecule annotation
2
Ubiquinol-cytochrome C Reductase Complex 6.4 KDA Protein(Gene symbol: UQCR11)
Molecule annotation
Chemicals (10 molecules)
1
6
2
2
3
2
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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