Isolation of photosynthetic membranes and submembranous particles from the cyanobacterium synechococcus PCC 7942

• Main Author: Horken, Kempton M.
• Other Authors: Ball State University. Dept. of Biology.
• Format: Others
• Published: 2011
• Subjects: Cyanobacteria > Physiology.; Photosynthetic bacteria.; Cell membranes.; Photosynthesis.; Metalloproteins.
• Online Access: http://cardinalscholar.bsu.edu/handle/handle/185580; http://liblink.bsu.edu/uhtbin/catkey/1036184

Photosynthetic membranes were prepared from the cyanobacterium Synechococcus PCC 7942 with oxygen evolving specific activity of 250-300 µmoles 02/ mg chl/hr. The membranes retained activity with a half-life of 4-5 days when stored at 0°C, or when quickly frozen in liquid nitrogen, greater than 95% of the activity remained after 2 months. Attempts to purify homogeneous preparations of photosystem II complexes from these membranes by detergent extraction were unsuccessful as indicated by a lack of a significant increase in oxygen evolution specific activity of the detergent extracts. Photosynthetic membrane detergent extracts usually maintained the same oxygen evolution specific activity as the orginal membranes, and a considerable amount of Photosystem I activity (75 µmoles 02 consumed /mg chl/hr in the Mehler reaction) was still present. The donor side of the photosystem II particles in the detergent extract was intact since the artificial electron acceptor, 2,6-dichiorophenolindophenol (DCPIP), was reduced at a rate comparable to the oxygen evolving activity. All oxygen evolving activity of the detergent extracts was lost when ion-exchange chromatography was used to resolve the co-extracted photosystem II and photosystem I complexes. === Department of Biology