Photosynthetic oxygen evolution does not require the participation of polypeptides of 16 and 24 kilodaltons.
Oxygen evolution from Triton X-100 prepared photosystem II particles from spinach was inhibited 70-80% after treatment of the particles with high concentrations of salt (0.5 or 1 M NaCl). The salt-washed preparations were depleted of 16 and 24 kilodalton polypeptides. Nearly complete restoration of herbicide-sensitive electron transport activity was observed upon addition of Cl-. Maintenance of the maximal rates required the presence of Ca2+. Restoration of the activity did not require the readdition (reconstitution) of the extracted polypeptides indicating that the 16 and 24 kilodalton polypeptides do not participate directly in the water-oxidation process. They may, however, play a regulatory role, e.g., in the sequestering of Cl- and/or Ca2+.
D004579:Electron Transport; D008970:Molecular Weight; D010100:Oxygen / Q000302:isolation & purification*; D010455:Peptides / Q000502:physiology*; D010788:Photosynthesis; D010940:Plant Proteins / Q000502:physiology; D010944:Plants / Q000378:metabolism
D010455:Peptides; D010940:Plant Proteins; D010100:Oxygen