Electric linear dichroism of chromatophores, pigment-protein and reaction center complexes derived from Rhodopseudomonas spheroides

The pulsed electric field linear dichroism technique is utilized to study the orientations of pigments in antenna bacteriochlorophyll-protein and reaction center complexes, and chromatophores isolated from the photosynthetic bacterium Rhodopseudomonas spheroides. The protein complexes tend to be oriented with their longest dimensions parallel to the membrane planes. The electric dichroism method is particularly suitable for studying the linear dichroism and orientation of the aromatic amino acid residues with absorption bands below 300nm.