Primary Citation of Related Structures:   6K61
PubMed Abstract: 
Two large protein-cofactor complexes, photosystem I and photosystem II, are the central components of photosynthesis in the thylakoid membranes. Here, we report the 2.37-Å structure of a tetrameric photosystem I complex from a heterocyst-forming cyanobacterium Anabaena sp. PCC 7120. Four photosystem I monomers, organized in a dimer of dimer, form two distinct interfaces that are largely mediated by specifically orientated polar lipids, such as sulfoquinovosyl diacylglycerol. The structure depicts a more closely connected network of chlorophylls across monomer interfaces than those seen in trimeric PSI from thermophilic cyanobacteria, possibly allowing a more efficient energy transfer between monomers. Our physiological data also revealed a functional link of photosystem I oligomerization to cyclic electron flow and thylakoid membrane organization.
Organizational Affiliation: 
State Key Laboratory of Membrane Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing, China.
State Key Laboratory of Protein and Plant Genetic Engineering, School of Life Sciences, Peking University, Beijing, China.
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China. ghli@dicp.ac.cn.
State Key Laboratory of Protein and Plant Genetic Engineering, School of Life Sciences, Peking University, Beijing, China. jzhao@pku.edu.cn.
Chinese Academy of Sciences Key Laboratory of Phycological Research, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China. jzhao@pku.edu.cn.
State Key Laboratory of Membrane Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing, China. gaon@pku.edu.cn.