The isolated Photosystem II reaction center: first attempts to directly measure the kinetics of primary charge separation

A Significant Loss in Photosynthetic Activity Associated with the Yellow Vine Syndrome of Cranberry

“…Chlorophyll fluorescence analysis. The kinetics of the electron transfer steps in photosynthetic reaction centers has been thoroughly investigated over the complete timescale of femtoseconds to many seconds (Brudvig, 2008;Govindjee and Seibert, 2010;Rappaport and Diner, 2008;Renger and Holzwarth, 2005;Seibert and Wasielewski, 2003;van Grondelle and Gobets, 2004). The early electron transfer occurring in PSII revealed by ultrafast spectroscopy can be divided into several steps: 1) absorption of light quanta by antenna to form excited states of pigments; 2) trapping of excitation energy by the primary electron donor P 680 in the reaction center on the picosecond time scale; 3) primary charge separation from the singlet excited state of P 680 to the primary acceptor Pheo in %3 to 20 ps; 4) stabilization of the separated charges from the radical pair P 680 + Pheoon the acceptor side by electron transfer to Q A in %200 ps and to Q B on the hundreds-of-ms time scale; and 5) on the donor side, an electron is supplied to reduce P 680 + from water through a tyrosine residue (Y Z ) and Mn 4 Ca cluster involving a S-state oxygen evolution cycle on the ns-ms time scale (Brudvig, 2008;Debus, 1992;Diner and Babcock, 1996;Kok and Radmer, 1976;Rutherford et al, 1992;Tommos and Babcock, 2000).…”

The Mystery of Oxygen Evolution: Analysis of Structure and Function of Photosystem II, the Water-Plastoquinone Oxido-Reductase

“…½D þ À P À A À where P represents the trap P680, D represents primary donor to P, and A represents primary acceptor. However, obtaining direct information on the physical and chemical nature of primary charge separators and primary reactions were not possible until the development of fast absorption spectroscopy (see also reviews by Mathis 1977;Klimov 2003;Seibert et al 2003 Absorption, migration, and utilization of light energy Absorption of light energy is the fastest phenomenon in photosynthesis occurring in femtosecond range. The light energy absorbed by the antenna pigments migrates to the reaction center.…”

“…The technique yields information on a number of fluorescence transients with different lifetimes. Plant efficiency analyzer (PEA) and pulse amplitude modulated (PAM) fluorometer are two major devices to record fluorescence and yield information on fluorescence transients, photochemical quenching (qP), and non-photochemical quenching (qN) of fluorescence (Strasser et al 2000(Strasser et al , 2004Schreiber 2004).…”

Biology and biotechnological applications of microalgae and photosynthetic prokaryotes: part 2

“…Accurate measurements were difficult at the time due to the extreme light-, oxygen-, and temperature-sensitivity of the PS II chlorophyllprotein complexes, but we did not 'give-up'. For summary of this work, see Seibert and Wasielewski (2005) and Govindjee and Seibert (2010). In addition, in 1990, Govindjee and I collaborated, in work done at the University of Illinois at Urbana-Champaign, UIUC, on fluorescence lifetime distributions in isolated PS II RCPs .…”