Purification and crystallization of the entire recombinant subunit E of the energy producer A(1)A(o) ATP synthase.

A(1)A(o) ATP synthases are the major energy producers in archaea. Subunit E of the stator domain of the ATP synthase from Pyrococcus horikoshii OT3 was cloned, expressed and purified to homogeneity. The monodispersed protein was crystallized by vapour diffusion. A complete diffraction data set was collected to 3.3 A resolution with 99.4% completeness using a synchrotron-radiation source. The crystals belonged to space group I4, with unit-cell parameters a = 112.51, b = 112.51, c = 96.25 A, and contained three molecules in the asymmetric unit.