2001
Quantifying the Ion Selectivity of the Ca2+ Site in Photosystem II: Evidence for Direct Involvement of Ca2+ in O2 Formation †
Vrettos J, Stone D, Brudvig G. Quantifying the Ion Selectivity of the Ca2+ Site in Photosystem II: Evidence for Direct Involvement of Ca2+ in O2 Formation †. Biochemistry 2001, 40: 7937-7945. PMID: 11425322, DOI: 10.1021/bi010679z.Peer-Reviewed Original ResearchConceptsOxygen-evolving complexTrivalent metal ionsMetal ionsPSII samplesPhotosystem IISubstrate water moleculesSmall metal ionsO2 evolutionSteady-state enzyme kineticsWater oxidationAqua ionsWater moleculesLewis acidO2 formationIonic radiusIon selectivityKcal/Monovalent ionsIonsExtrinsic polypeptidesFree energyEnzyme kineticsStructural cofactorSr2Activity measurements
1986
Effect of the 17- and 23-kilodalton polypeptides, calcium, and chloride on electron transfer in photosystem II.
De Paula J, Li P, Miller A, Wu B, Brudvig G. Effect of the 17- and 23-kilodalton polypeptides, calcium, and chloride on electron transfer in photosystem II. Biochemistry 1986, 25: 6487-94. PMID: 3024710, DOI: 10.1021/bi00369a022.Peer-Reviewed Original ResearchConceptsS2-state multiline EPR signalMultiline EPR signalEPR signalPSII membranesPhotosystem II samplesS1 stateUntreated PSII membranesReaction centersElectron paramagnetic resonance measurementsChlorophyll moleculesPhotosystem II membranesStable charge separationParamagnetic resonance measurementsPhotosystem IIPSII samplesO2-evolving centerElectron transferCharge separationElectron donorNuclear hyperfine structureCytochrome b559Mn sitesResonance measurementsOxidationFraction of PSII