Protein ligation of the photosynthetic oxygen-evolving center

Architecture of the photosynthetic oxygen-evolving center.

Photosynthesis uses light energy to drive the oxidation of water at an oxygen-evolving catalytic site within photosystem II (PSII). We report the structure of PSII of the cyanobacterium Thermosynechococcus elongatus at 3.5 angstrom resolution. We have assigned most of the amino acid residues of this 650-kilodalton dimeric multisubunit complex and refined the structure to reveal its molecular ar...

XAS of Mn in the Photosynthetic Oxygen, Evolving Complex

Nearly all of the dioxygen which animals and aerobic bacteria use during respiration originates from the photosynthetic oxygen evolving complex (OEC) which is found in the chloroplast thylakoid membranes of higher plants and algae. Four specifically bound Mn are required for OEC activity [l]. These manganese do not exhibit the six line epr spectrum which is characteristic of Mn(IIj in solution,...

Time-resolved vibrational spectroscopy detects protein-based intermediates in the photosynthetic oxygen-evolving cycle.

Photosynthetic oxygen production by photosystem II (PSII) is responsible for the maintenance of aerobic life on earth. The production of oxygen occurs at the PSII oxygen-evolving complex (OEC), which contains a tetranuclear manganese (Mn) cluster. Photo-induced electron transfer events in the reaction center lead to the accumulation of oxidizing equivalents on the OEC. Four sequential photooxid...

Glycinebetaine stabilizes the association of extrinsic proteins with the photosynthetic oxygen-evolving complex.

The photosynthetic oxygen-evolving activity of the photosystem 2 complex, prepared from spinach, was labile when the complex was exposed to high-salt conditions under which the extrinsic proteins were dissociated from the complex. Glycinebetaine prevented the dissociation of the 18-kDa and the 23-kDa extrinsic proteins from the photosystem 2 complex in the presence of 1 M NaCl. It also prevente...

Function of Extrinsic Proteins in Stabilization of the Photosynthetic Oxygen-Evolving Complex