Preparation and Characterization of Heat-Stable and Very Active Oxygen-Evolving Photosystem II Particles from the Thermophilic Cyanobacterium, Synechococcus elongatu

1992 ◽  
Vol 33 (3) ◽  
pp. 299-305 ◽  
Author(s):  
Toshiaki Ichimura ◽  
Sachio Miyairi ◽  
Kazuhiko Satoh ◽  
Sakae Katoh
Keyword(s):  
Photosystem Ii ◽  
Active Oxygen ◽  
Heat Stable ◽  
Thermophilic Cyanobacterium ◽  
Oxygen Evolving ◽  
Photosystem Ii Particles

Characterization of photosystem II with the atomic-force microscope

1992 ◽  
Vol 50 (2) ◽  
pp. 1146-1147
Author(s):  
Kathleen M. Marr ◽  
Mary K. Lyon
Keyword(s):  
Photosystem Ii ◽  
Atomic Force Microscope ◽  
Three Dimensional ◽  
Biologically Active ◽  
Atomic Force ◽  
Freeze Etching ◽  
Image Averaging ◽  
Oxygen Evolving ◽  
Averaging Techniques

Photosystem II (PSII) is different from all other reaction centers in that it splits water to evolve oxygen and hydrogen ions. This unique ability to evolve oxygen is partly due to three oxygen evolving polypeptides (OEPs) associated with the PSII complex. Freeze etching on grana derived insideout membranes revealed that the OEPs contribute to the observed tetrameric nature of the PSIl particle; when the OEPs are removed, a distinct dimer emerges. Thus, the surface of the PSII complex changes dramatically upon removal of these polypeptides. The atomic force microscope (AFM) is ideal for examining surface topography. The instrument provides a topographical view of individual PSII complexes, giving relatively high resolution three-dimensional information without image averaging techniques. In addition, the use of a fluid cell allows a biologically active sample to be maintained under fully hydrated and physiologically buffered conditions. The OEPs associated with PSII may be sequentially removed, thereby changing the surface of the complex by one polypeptide at a time.

Characterization of a resolved oxygen-evolving Photosystem II preparation from spinach thylakoids

1983 ◽  
Vol 724 (2) ◽  
pp. 201-211 ◽  
Author(s):  
Eric Lam ◽  
Barbara Baltimore ◽  
William Ortiz ◽  
Susan Chollar ◽  
Anastasios Melis ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Oxygen Evolving ◽  
Spinach Thylakoids
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