STRUCTURE AND FUNCTION IN BACTERIAL 

 PHOTOSYNTHESIS 1 



HOWARD GEST and SUBIR K. BOSE 



The Henry Shaiv School of Botany 



and the Adolphus Busch III Laboratory of Molecular Biology, 



Washington University, St. Louis, Missouri 



In the concluding section of his recent monograph on Synthesis and 

 Organisation in the Bacterial Cell, E. F. Gale (1) comments: "The 

 title should also include 'disorganisation,' as most of the results dis- 

 cussed in these pages have been concerned with the consequences of 

 disorganisation— frequently on so drastic a scale that it is a miracle 

 that anything of significance survives," 



During the past decade, our understanding of bacterial photosyn- 

 thesis has been greatly increased through the study of biochemical 

 activities which survive the violent cell-disruption procedures com- 

 monly used (sonic oscillation, grinding with alumina, French pressure 

 cell). In fact, the discovery (2) that pigmented subcellular particles 

 ("chromatophores") from R. ruhrum and similar bacteria catalyze an 

 anaerobic light- dependent phosphorylation of ADP has led to a pro- 

 found revision of views on the fundamental features of the overall 

 bacterial process. On the other hand, reflection on the recent history 

 of analysis of other multi- component processes of comparable com- 

 plexity {e.g., mitochondrial electron transfer and oxidative phosphory- 

 lation) suggests that it would indeed be remarkable if particles ob- 

 tained by the methods noted retained all of the biochemical capacities 

 characteristic of the photochemical "apparatus" in its native state. 



The foregoing considerations provided the stimulus for earlier 

 studies (3,4) on isolation of the particulate photochemical system by 

 milder procedures. In particular, osmotic lysis of protoplasts appeared 

 to represent a potentially ideal approach. The initial experiments (3) 

 surprisingly revealed that upon osmotic lysis of R. nibriim proto- 

 plasts2 (prepared by treatment with lysozyme + EDTA) the pigment 

 system was not released but, rather, was retained in the membranous 

 "ghost" structures. In sharp contrast with particles obtained by drastic 

 methods of cell breakage, the pigmented "ghosts" are sedimentable 



1 Supported by grants from the U. S. Public Health Service (E-2640) and the 

 National Science Foundation (G-9877). 



2 This term is used with the understanding that the cell-forms referred to are 

 not entirely analogous to the protoplasts of Gram-positive bacteria. 



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