Dynamics of electron transfer in photosystem II.
Photosystem II, being a constituent of light driven photosynthetic apparatus, is a highly organized pigment-protein-lipid complex. The arrangement of PSII active redox cofactors insures efficiency of electron transfer within it. Donation of electrons extracted from water by the oxygen evolving complex to plastoquinones requires an additional activation energy. In this paper we present theoretical discussion of the anharmonic fluctuations of the protein-lipid matrix of PSII and an experimental evidence showing that the fluctuations are responsible for coupling of its donor and acceptor side. We argue that the fast collective motions liberated at temperatures higher that 200 K are crucial for the two final steps of the water splitting cycle and that one can distinguish three different dynamic regimes of PSII action which are controlled by the timescales of forward electron transfer, which vary with temperature. The three regimes of the dynamical behavior are related to different spatial domains of PSII.
Burda
Kvetoslava
K
Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland. burda@novell.ftj.agh.edu.pl
D000818:Animals; D001703:Biophysics / Q000379:methods; D016825:Chlamydomonas reinhardtii / Q000378:metabolism; D003573:Cytochrome b Group / Q000737:chemistry; D004563:Electrochemistry; D004583:Electrons; D008954:Models, Biological; D008956:Models, Chemical; D010084:Oxidation-Reduction; D045322:Photosynthetic Reaction Center Complex Proteins / Q000502:physiology; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000502:physiology*; D015204:Spectroscopy, Mossbauer; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
D003573:Cytochrome b Group; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D014867:Water; C019313:cytochrome b559