AN IMPROVED PURIFICATION OF ECF1 AND ECF1F0 BY USING A CYTOCHROME BO-DEFICIENT STRAIN OF ESCHERICHIA-COLI FACILITATES CRYSTALLIZATION OF THESE COMPLEXES

A novel strategy, which employs a cytochrome bo-lacking strain (GO104) and a modified isolation procedure provides an effective approach for obtaining much purer preparations of ECF1F0 than described previously , as web as for isolating homogeneous and protein-chemically pure ECF1 . ECF1 obtained in this way could be crystallized by vapor-diffusion u sing polyethylene glycol (PEG) as a precipitant in a form suitable for X-ray diffraction analysis. The crystals belong to the orthorhombic s pace group P2(1)2(1)2(1), with lattice parameters a = 110, b = 134, an d c = 269 Angstrom, and diffract to a resolution of at least 6.4 Angst rom. (C) 1997 Federation of European Biochemical Societies.