Isolation, characterisation and crystallisation of a water-soluble fragment of the Rieske iron-sulfur protein of bovine heart mitochondrial bc1 complex.
A water-soluble fragment of the bc1 complex from bovine heart mitochondria was isolated containing the intact Rieske [2Fe-2S] cluster. The fragment consists of the last 129 amino acid residues of the Rieske iron-sulfur protein and has a molecular mass of 14592 Da including two iron atoms. The absorption, visible CD, and EPR spectra of the fragment are indistinguishable from those of the membrane-bound iron-sulfur protein. The redox potential as determined by EPR-monitored redox titration was + 306 mV. The far-ultraviolet CD spectrum is indicative of a protein with little regular secondary structure, while significant alpha-helix content was detected in the membrane anchor of the complete iron-sulfur protein. The fragment could be crystallized using poly(ethylene glycol) 6000 as precipitant. Needle-shaped single crystals have been grown by the hanging-drop vapor diffusion technique. These crystals belong to the space group P21 and diffract well beyond 0.2 nm resolution. Phase determination using the multiple-wavelength anomalous-scattering technique is underway.
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Universitätsklinikum Frankfurt, ZBC, Germany.
Saynovits
M
M
Assmann
C
C
Iwata
S
S
Ohnishi
T
T
von Jagow
G
G
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D003460:Crystallization; D004578:Electron Spin Resonance Spectroscopy; D014450:Electron Transport Complex III / Q000737:chemistry*; D006868:Hydrolysis; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D008929:Mitochondria, Heart / Q000201:enzymology*; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary
D007506:Iron-Sulfur Proteins; C037989:Rieske iron-sulfur protein; D014450:Electron Transport Complex III