Crystallization and characterization of Chromatium vinosum cytochrome c'.

The dimeric high spin c-type cytochrome c' from Chromatium vinosum has been crystallized and the crystals characterized by x-ray diffraction. This cytochrome c' exhibits ligand-controlled dissociation from a dimer to a monomer upon binding carbon monoxide and represents an opportunity to obtain unique information concerning cooperativity in heme proteins. The C. vinosum cytochrome c' protein crystals are grown from polyethylene glycol 4000 and grow in both space group P2(1)2(1)2(1) (a = 49.2, b = 56.7, c = 98.8 A) and space group P2(1) (a = 55, b = 94, c = 50, beta = 106.1 A) depending upon the growth rate, with the P2(1)2(1)2(1) form favored at slower growth rates. The high resolution (2.0 A) atomic structure of the P2(1)2(1)2(1) form is being determined.