Water‐soluble 17 and 23 kDa polypeptides restore oxygen evolution activity by creating a high‐affinity binding site for Ca2+ on the oxidizing side of Photosystem II
Authors:
- Demetrios F. GhanotakisDGDemetrios F. Ghanotakis
- James N. TopperJTJames N. Topper
- Gerald T. BabcockGBGerald T. Babcock
- Charles F. YocumCYCharles F. Yocum
- 7 May 1984
- journal article
- Published by Wiley in FEBS Letters
- Vol. 170 (1) , 169-173
Abstract
Exposure of detergent‐isolated preparations of the Photosystem II complex to 2 M NaCl releases water‐soluble 17 and 23 kDa polypeptides; the inhibited rate of oxygen evolution activity is stimulated by addition of Ca2+ [(1984) FEBS Lett. 167, 127–130]. Reactivation of oxygen evolution activity by Ca2+ requires the presence of the ion in high (mM) non‐physiological concentrations. Using a new dialysis‐reconstitution procedure we have shown that rebinding of the 17 and 23 kDa polypeptides restores oxygen evolution activity only when the system has not been pretreated with EGTA. Removal of loosely‐bound Ca2+ from the salt‐extracted PS II complex and from the polypeptide solution, by dialysis against EGTA, blocks reconstitution of oxygen evolution activity even though the two polypeptides do rebind; restoration of Ca2+ to EGTA‐treated systems, after rebinding of the 17 and 23 kDa polypeptides, results in a strong reconstitution of oxygen evolution activity. The effect of rebound 17 and 23 kDa polypeptides is to promote high affinity binding of Ca2+ to the reconstituted membrane.Keywords
This publication has 12 references indexed in Scilit:
- Calcium reconstitutes high rates of oxygen evolution in polypeptide depleted Photosystem II preparationsFEBS Letters, 1984
- Structure and mechanism of copper, zinc superoxide dismutaseNature, 1983
- Partial disintegration and reconstitution of the photosynthetic oxygen evolution system. Binding of 24 kilodalton and 18 kilodalton polypeptidesBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1983
- A Calcium-Selective Site in Photosystem II of Spinach ChloroplastsPlant Physiology, 1983
- Reversible inhibition of photochemistry of photosystem II by Ca2+ removal from intact cells of Anacystis nidulansFEBS Letters, 1983
- Hydroxylamine as an inhibitor between Z and P680 in photosystem IIFEBS Letters, 1983
- A requirement for Ca2+ in the extraction of O2-evolving Photosystem 2 preparations from the cyanobacterium Anacystis nidulansBiochemical Journal, 1983
- FACTORS REQUIRED FOR PHOTOACTIVATION OF THE LATENT OXYGEN-EVOLVING SYSTEM: SOME NEW FINDINGS DERIVED FROM INTACT CHLOROPLAST SYSTEM1983
- Reconstitution of photosynthetic water splitting in inside-out thylakoid vesicles and identification of a participating polypeptideBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1982
- Calcium and photosynthetic oxygen evolution in cyanobacteriaBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1978