Overexpression, purification, crystallization and data collection of Sulfolobus solfataricus Sso6206, a novel highly conserved protein

Sso6206, a 10.5 kDa protein from Sulfolobus solfataricus, has been overexpressed, purified and crystallized. The protein crystallizes in space group P6(1/5)22, with unit-cell parameters a = b = 157.8, c = 307.3 A. The crystals are hexagonal bipyramids and a data set has been collected to 2.4 A resolution. Molecular replacement cannot be attempted as no convincing model can be identified. Crystals of selenomethionine-variant protein have not yet been obtained. Interestingly, crystal packing, gel filtration and mass spectrometry all suggest the native protein forms a multi-subunit oligomer consisting of >9 subunits.