Purification and two-dimensional crystallization of highly active cytochrome b(6)f complex from spinach

The purification and two-dimensional crystallization of highly active cytoc hrome b(6)f complex from spinach is described. The preparation shows all sp ectroscopic characteristics of the pure complex. The electron transfer acti vity of 450 +/- 60 electrons per s is the highest in vitro activity reporte d to date. Using dimethyl sulfoxide (DMSO) as a solvent for the electron do nor enhanced the performance and reproducibility of the assay. The high yie ld and the high activity of the protein make it an ideal candidate for biop hysical and structural studies. Preliminary two-dimensional crystallization experiments yielded several different forms of two-dimensional and thin th ree-dimensional crystals, exhibiting varying degrees of order. (C) 1999 Fed eration of European Biochemical Societies.