A Functional Role for Tyrosine-D in Assembly of the Inorganic Core of the Water Oxidase Complex of Photosystem II and the Kinetics of Water Oxidation†

摘要: The role of D2-Tyr160 (YD), a photooxidizable residue in the D2 reaction center polypeptide photosystem II (PSII), was investigated both wild type and mutant strain (D2-Tyr160Phe) which phenylalanine replaces YD cyanobacterium Synechocystis sp. (strain PCC 6803). is symmetry-related tyrosine that homologous to essential photoactive Tyr161(YZ) D1 PSII. We compared flash-induced yield O2 intact, functional PSII centers from wild-type core complexes. intact holo-enzyme found be identical cores using long (saturating) pulses or continuous illumination, but observed appreciably reduced short (nonsaturating) light (<50 ms). also rates first two kinetically resolved steps photoactivation. Photoactivation assembly process for binding inorganic cofactors apo-water oxidation/PSII complex...