THE EXPRESSION, PURIFICATION AND CRYSTALLIZATION OF THE EPSILON-SUBUNIT OF THE F(1) PORTION OF THE ATPASE OF ESCHERICHIA-COLI

The ε subunit of the F0F1-ATPase from Escherichia coli has been expressed in E. coli as a fusion protein with glutathione S-transferase from the parasitic helminth Schistosoma japonicum. The ε subunit released by thrombin treatment of the purified fusion protein carried two amino acid changes. A1G and M2S, and was obtained in a yield of about five milligrams per litre of cultured cells. The two amino acid changes were shown not to affect function. The protein has been crystallized in a form suitable for X-ray diffraction structure analysis. The crystals are hexagonal, space group P6122 (or P6522), with a = b = 94.9 A ̊, c = 57.1 A ̊ and γ = 120 °. The diffraction from small crystals extends to at least 2.9 Å resolution. © 1992.