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-Structure paper
Title | Pea PSII-LHCII supercomplexes form pairs by making connections across the stromal gap. |
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Journal, issue, pages | Sci Rep, Vol. 7, Issue 1, Page 10067, Year 2017 |
Publish date | Aug 30, 2017 |
Authors | Pascal Albanese / Roberto Melero / Benjamin D Engel / Alessandro Grinzato / Paola Berto / Marcello Manfredi / Angelica Chiodoni / Javier Vargas / Carlos Óscar Sánchez Sorzano / Emilio Marengo / Guido Saracco / Giuseppe Zanotti / Jose-Maria Carazo / Cristina Pagliano / |
PubMed Abstract | In higher plant thylakoids, the heterogeneous distribution of photosynthetic protein complexes is a determinant for the formation of grana, stacks of membrane discs that are densely populated with ...In higher plant thylakoids, the heterogeneous distribution of photosynthetic protein complexes is a determinant for the formation of grana, stacks of membrane discs that are densely populated with Photosystem II (PSII) and its light harvesting complex (LHCII). PSII associates with LHCII to form the PSII-LHCII supercomplex, a crucial component for solar energy conversion. Here, we report a biochemical, structural and functional characterization of pairs of PSII-LHCII supercomplexes, which were isolated under physiologically-relevant cation concentrations. Using single-particle cryo-electron microscopy, we determined the three-dimensional structure of paired CSM PSII-LHCII supercomplexes at 14 Å resolution. The two supercomplexes interact on their stromal sides through a specific overlap between apposing LHCII trimers and via physical connections that span the stromal gap, one of which is likely formed by interactions between the N-terminal loops of two Lhcb4 monomeric LHCII subunits. Fast chlorophyll fluorescence induction analysis showed that paired PSII-LHCII supercomplexes are energetically coupled. Molecular dynamics simulations revealed that additional flexible physical connections may form between the apposing LHCII trimers of paired PSII-LHCII supercomplexes in appressed thylakoid membranes. Our findings provide new insights into how interactions between pairs of PSII-LHCII supercomplexes can link adjacent thylakoids to mediate the stacking of grana membranes. |
External links | Sci Rep / PubMed:28855679 / PubMed Central |
Methods | EM (single particle) |
Resolution | 14.0 Å |
Structure data | EMDB-3825: |
Source |
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