Crystallization of [Fe3S4]-ferredoxin from the hyperthermophile archaeon Pyrococcus furiosus

Recombinant Pyrococcus furiosus ferredoxin with a [Fe3S4]-cluster was crystallized through steps of optimization and X-ray diffraction data were collected from several crystal forms. Flat plate-like crystals were grown by hanging-drop vapour diffusion. The precipitant used was 30% PEG 400; the pH was varied between 7.0 and 8.0 and hexaamminecobalt(III) chloride was essential for crystal formation. The best crystals belong to space group P2(1), with unit-cell parameters a = 31.23, b = 47.51, c = 52.03 A, beta = 103.86 degrees, and diffract to 1.5 A resolution.