Photosystem II reaction center particle from Spirodela stroma lamellae.

A Photosystem II (PSII) reaction center particle from the stroma lamellae of Spirodela oligorrhiza has been isolated. The stroma lamellar PSII reaction center contained the same proteins found in granal PSII reaction centers, namely D1, D2, and cytochrome b559; however, the cytochrome b559 content was half of that in the granal centers. The pigment composition, 77 K fluorescence emission, and excitation spectra of the stroma lamellar reaction centers were determined. Our results indicate a fully functional PSII particle in the stromal lamellae.