ABSTRACT
The light-reactions of bacterial photosynthesis take place in and on the highly pigmented intracytoplasmic membranes. This chapter describes the molecular details of the light-harvesting process in purple photosynthetic bacteria. It aims to obtain a high resolution three-dimensional structure for a bacterial antenna complex and describes some experiences in this area of crystallizing membrane proteins. The bacterial antenna complexes are rather ideal proteins to use to study the general methods for crystallizing membrane proteins. The chapter explains the purification of the B800-850-complex from Rhodobacter sphaeroides strain. The success in obtaining crystals with a bacterial antenna complex was using the B800-850-complex from Rps. acidophila strain 7750. The basis of the method we use to crystallize the antenna complexes relies upon the addition of small amphiphiles. Both Hartmut Michel and R. Michael Garavito have also emphasized a second role of the small amphiphiles in the actual process of crystal formation.
