PDBsum entry 1rie

Electron transport

PDB id: 1rie

Contents

Protein chain

127 a.a. *

Ligands

FES

Waters ×167

* Residue conservation analysis

PDB id:

1rie

Name:

Electron transport

Title:

Structure of a water soluble fragment of the rieske iron-sulfur protein of the bovine heart mitochondrial cytochrome bc1-complex

Structure:

Rieske iron-sulfur protein. Chain: a. Fragment: soluble fragment. Synonym: ubiquinol-cytochromE C reductase iron-sulfur. Ec: 1.10.2.2

Source:

Bos taurus. Cattle. Organism_taxid: 9913. Organ: heart. Organelle: mitochondria

Resolution:

1.50Å R-factor: 0.187 R-free: 0.211

Authors:

S.Iwata,M.Saynovits,T.A.Link,H.Michel

Key ref:

S.Iwata et al. (1996). Structure of a water soluble fragment of the 'Rieske' iron-sulfur protein of the bovine heart mitochondrial cytochrome bc1 complex determined by MAD phasing at 1.5 A resolution. Structure, 4, 567-579. PubMed id: 8736555 DOI: 10.1016/S0969-2126(96)00062-7

Date:

23-Feb-96 Release date: 07-Dec-96

Protein chain

P13272  (UCRI_BOVIN) -  Cytochrome b-c1 complex subunit Rieske, mitochondrial from Bos taurus

Seq: 274 a.a.

Struc: 127 a.a.

Enzyme reactions

• Enzyme class: E.C.7.1.1.8 - quinol--cytochrome-c reductase.
• Reaction: a quinol + 2 Fe(III)-[cytochrome c](out) = a quinone + 2 Fe(II)- [cytochrome c](out) + 2 H(+)(out)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Key reference

DOI no: 10.1016/S0969-2126(96)00062-7

Structure 4:567-579 (1996)

PubMed id: 8736555

Structure of a water soluble fragment of the 'Rieske' iron-sulfur protein of the bovine heart mitochondrial cytochrome bc1 complex determined by MAD phasing at 1.5 A resolution.

S.Iwata, M.Saynovits, T.A.Link, H.Michel.

ABSTRACT

BACKGROUND: The 'Rieske' iron-sulfur protein is the primary electron acceptor during hydroquinone oxidation in cytochrome bc complexes. The spectroscopic and electrochemical properties of the 'Rieske' [2Fe-2S] cluster differ significantly from those of other iron-sulfur clusters. A 129-residue water soluble fragment containing the intact [2Fe-2S] cluster was isolated following proteolytic digestion of the bc1 complex and used for structural studies. RESULTS: The structure of the Rieske iron-sulfur fragment containing the reduced [2Fe-2S] cluster has been determined using the multiwavelength anomalous diffraction (MAD) technique and refined at 1.5 A resolution. The fragment has a novel overall fold that includes three sheets of beta strands. The iron atoms of the [2Fe-2S] cluster are coordinated by two cysteine (Fe-1) and two histidine (Fe-2) residues, respectively, with the histidine ligands completely exposed to the solvent. This is in contrast to the four cysteine coordination pattern observed in previously characterised [2Fe-2S] ferredoxins. The cluster-binding fold is formed by two loops connected by a disulfide bridge; these loops superpose with the metal-binding loops of rubredoxins. The environment of the cluster is stabilised by an extensive hydrogen-bond network. CONCLUSIONS: The high-resolution structure supports the proposed coordination pattern involving histidine ligands and provides a basis for a detailed analysis of the spectroscopic and electrochemical properties. As the cluster is located at the tip of the protein, it might come into close contact with cytochrome b. The exposed N epsilon atoms of the histidine ligands of the cluster are readily accessible to quinones and inhibitors within the hydroquinone oxidation (QP) pocket of the bc1 complex and may undergo redox-dependent protonation/deprotonation.

Selected figure(s)

Figure 3.
Figure 3. Topology of the ISF. The hydrogen-bond pattern and secondary structure assignment are indicated. The residues conserved in all known Rieske iron–sulfur proteins from cytochrome bc[1] complexes are printed in red. The outlined characters denote residues missing in Rieske iron–sulfur protein from the cytochrome b[6]^f complex. Metal ligands and residues that form a disulfide bridge are colored yellow and green, respectively. Figure 3. Topology of the ISF. The hydrogen-bond pattern and secondary structure assignment are indicated. The residues conserved in all known Rieske iron–sulfur proteins from cytochrome bc[1] complexes are printed in red. The outlined characters denote residues missing in Rieske iron–sulfur protein from the cytochrome b[6]^f complex. Metal ligands and residues that form a disulfide bridge are colored yellow and green, respectively.

Figure 6.
Figure 6. Electrostatic surface properties of the ISF. Molecular surface of ISF color-coded by electrostatic potential: red, negative; blue, positive. The extreme ranges of red and blue represent electrostatic potentials of −5 and +5 k[B]T, respectively (k[B], Boltzmann constant; T, temperature). The view shows the same orientation as Figure 2a. The figure was generated using the program GRASP [50]. Figure 6. Electrostatic surface properties of the ISF. Molecular surface of ISF color-coded by electrostatic potential: red, negative; blue, positive. The extreme ranges of red and blue represent electrostatic potentials of −5 and +5 k[B]T, respectively (k[B], Boltzmann constant; T, temperature). The view shows the same orientation as [3]Figure 2a. The figure was generated using the program GRASP [4][50].

The above figures are reprinted by permission from Cell Press: Structure (1996, 4, 567-579) copyright 1996.

Figures were selected by an automated process.