1. Exchange pathways of plastoquinone and plastoquinol in the photosystem II complex
- Author
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Xavier Periole, Floris J. van Eerden, Pim W. J. M. Frederix, Manuel N. Melo, Siewert J. Marrink, and Molecular Dynamics
- Subjects
0301 basic medicine ,Time Factors ,photosystem II complex ,Photosystem II ,Plastoquinone ,Science ,General Physics and Astronomy ,Molecular Dynamics Simulation ,Photosynthesis ,Models, Biological ,Thylakoids ,General Biochemistry, Genetics and Molecular Biology ,Article ,Diffusion ,Electron Transport ,03 medical and health sciences ,chemistry.chemical_compound ,Molecular dynamics ,0302 clinical medicine ,Botany ,Multidisciplinary ,Cytochrome b6f complex ,platoquinone ,Photosystem II Protein Complex ,Oxidation reduction ,General Chemistry ,thylakoid membrane ,Electron transport chain ,Plant Leaves ,plastoquinol ,030104 developmental biology ,chemistry ,Thylakoid ,Biophysics ,Oxidation-Reduction ,030217 neurology & neurosurgery - Abstract
Plastoquinone (PLQ) acts as an electron carrier between photosystem II (PSII) and the cytochrome b6f complex. To understand how PLQ enters and leaves PSII, here we show results of coarse grained molecular dynamics simulations of PSII embedded in the thylakoid membrane, covering a total simulation time of more than 0.5 ms. The long time scale allows the observation of many spontaneous entries of PLQ into PSII, and the unbinding of plastoquinol (PLQol) from the complex. In addition to the two known channels, we observe a third channel for PLQ/PLQol diffusion between the thylakoid membrane and the PLQ binding sites. Our simulations point to a promiscuous diffusion mechanism in which all three channels function as entry and exit channels. The exchange cavity serves as a PLQ reservoir. Our simulations provide a direct view on the exchange of electron carriers, a key step of the photosynthesis machinery., Plastoquinone (PLQ) shuttles electrons between photosystem II (PSII) and cytochrome b6f. Here the authors perform molecular dynamics simulations and propose that PLQ enters the exchange cavity of PSII by a promiscuous diffusion mechanism whereby three different channels each act as entry and exit points.
- Published
- 2017