Crystallization and preliminary X‐ray diffraction studies of hyperthermophilic archaeal Rieske‐type ferredoxin (ARF) from Sulfolobus solfataricus P1

The hyperthermophilic archaeal Rieske‐type [2Fe–2S] ferredoxin (ARF) from Sulfolobus solfataricus P1 contains a low‐potential Rieske‐type [2Fe–2S] cluster that has served as a tractable model for ligand‐substitution studies on this protein family. Recombinant ARF harbouring a pET30a vector‐derived N‐terminal extension region plus a hexahistidine tag has been heterologously overproduced in Escherichia coli , purified and crystallized by the hanging‐drop vapour‐diffusion method using 0.05  M sodium acetate, 0.05  M HEPES, 2  M ammonium sulfate pH 5.5. The crystals diffracted to 1.85 Å resolution and belonged to the tetragonal space group P 4 3 2 1 2, with unit‐cell parameters a  = 60.72, c = 83.31 Å. The asymmetric unit contains one protein molecule.