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Right PSI in the cyclic electron transfer supercomplex NDH-PSI from ArabidopsisRight PSI in the cyclic electron transfer supercomplex NDH-PSI from Arabidopsis
Structural highlights
FunctionPSAA_ARATH PsaA and PsaB bind P700, the primary electron donor of photosystem I (PSI), as well as the electron acceptors A0, A1 and FX. PSI is a plastocyanin-ferredoxin oxidoreductase, converting photonic excitation into a charge separation, which transfers an electron from the donor P700 chlorophyll pair to the spectroscopically characterized acceptors A0, A1, FX, FA and FB in turn. Oxidized P700 is reduced on the lumenal side of the thylakoid membrane by plastocyanin. Publication Abstract from PubMedCyclic electron transport/flow (CET/CEF) in chloroplasts is a regulatory process essential for the optimization of plant photosynthetic efficiency. A crucial CEF pathway is catalyzed by a membrane-embedded NADH dehydrogenase-like (NDH) complex that contains at least 29 protein subunits and associates with photosystem I (PSI) to form the NDH-PSI supercomplex. Here, we report the 3.9 A resolution structure of the Arabidopsis thaliana NDH-PSI (AtNDH-PSI) supercomplex. We constructed structural models for 26 AtNDH subunits, among which 11 are unique to chloroplasts and stabilize the core part of the NDH complex. In the supercomplex, one NDH can bind up to two PSI-light-harvesting complex I (PSI-LHCI) complexes at both sides of its membrane arm. Two minor LHCIs, Lhca5 and Lhca6, each present in one PSI-LHCI, interact with NDH and contribute to supercomplex formation and stabilization. Collectively, our study reveals the structural details of the AtNDH-PSI supercomplex assembly and provides a molecular basis for further investigation of the regulatory mechanism of CEF in plants. Supramolecular assembly of chloroplast NADH dehydrogenase-like complex with photosystem I from Arabidopsis thaliana.,Su X, Cao D, Pan X, Shi L, Liu Z, Dall'Osto L, Bassi R, Zhang X, Li M Mol Plant. 2022 Mar 7;15(3):454-467. doi: 10.1016/j.molp.2022.01.020. Epub 2022 , Feb 2. PMID:35123031[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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