Structural studies of cytochrome reductase. Improved membrane crystals of the enzyme complex and crystallization of a subcomplex.

Membrane crystals of mitochondrial ubiquinol: cytochrome c reductase of improved size and long-range order and of the cytochrome bc1 subcomplex have been obtained by a dialysis method. The enzyme--Triton X-100 complex was mixed with Triton phospholipid micelles and the Triton slowly removed by dialysis for 48 hours at pH 5.5 at room temperature or above. The effect of varying the pH and temperature on the shape, size and order of the crystals is described.