An in vivo requirement for calcium in Photosystem II of Anacystis nidulans
Becker, D.W.; Brand, J.J.
Biochemical and Biophysical Research Communications 109(4): 1134-1139
ISSN/ISBN: 0006-291X PMID: 6820279 DOI: 10.1016/0006-291x(82)91895-2
Incubation under growth conditions in the absence of Ca2+ completely inhibited photosynthetic oxygen evolution in the cyanobacterium, Anacystisnidulans Anacystis nidulans. Addition of Ca2+ rapidly restored steady-state levels of oxygen evolution to these cells. Growth ceased in cultures devoid of Ca2+, but resumed to the normal rate subsequent to addition of Ca2+. Photosystem I activity remained at near normal rates in Ca2+-depleted cultures, demonstrating that the Ca2+ requirement is specific for Photosystem Ii in A. nidulans A. nidulans. The presence of glycylglycine or other Ca2+ chelater was required in the Ca2+-deficient growth medium in order to effectively inhibit Photosynthesis.