CRYSTALLIZATION AND X-RAY-ANALYSIS OF THE REACTION-CENTER FROM THE THERMOPHILIC GREEN BACTERIUM CHLOROFLEXUS-AUVANTIACUS

The photochemical reaction center of Chloroflexus (Cf.) aurantiacus, a membrane bound pigment-protein complex, has been crystallized in the presence of monodisperse polyoxyethylene detergents. The crystals poss essed a pronounced polymorphism. Three different crystal forms belongi ng to triclinic, monoclinic and orthorhombic space groups have been ch aracterized by X-ray analysis. The triclinic crystal form, with unit c ell dimensions of a = 88 Angstrom, b = 115 Angstrom and c 151 Angstrom , diffracts up to 3.2 Angstrom in two directions and to 4.0 Angstrom i n the third direction.