PSII-LHCII Supercomplex Organizations in Photosynthetic Membrane by Coarse-Grained Simulation

C.-K. Lee, C.-W. Pao, and B. Smit, PSII-LHCII Supercomplex Organizations in Photosynthetic Membrane by Coarse-Grained Simulation J Phys Chem B  119 (10), 3999 (2015) http://dx.doi.org/10.1021/jp511277c


Abstract: Green plant photosystem II (PSII) and light-harvesting complex II (LHCII) in the stacked grana regions of thylakoid membranes can self-organize into various PSII-LHCII supercomplexes with crystalline or fluid-like supramolecular structures to adjust themselves with external stimuli such as high/low light and temperatures, rendering tunable solar light absorption spectrum and photosynthesis efficiencies. However, the mechanisms controlling the PSII-LHCII supercomplex organizations remain elusive. In this work, we constructed a coarse-grained (CG) model of the thylakoid membrane including lipid molecules and PSII-LHCII supercomplex considering association/dissociation of moderately-bound-LHCIIs. The CG interaction between CG beads were constructed based on electron microscope (EM) experimental results, and we were able to simulate the PSII-LHCII supramolecular organization of a 500 × 500 nm2 thylakoid membrane, which is compatible with experiments. Our CGMD simulations can successfully reproduce order structures of PSII-LHCII supercomplexes under different protein packing fractions, free-LHCII:PSII ratios, and temperatures, thereby providing insights into mechanisms leading to PSII-LHCII supercomplex organizations in photosynthetic membrane.

© Berend Smit 2019