Cyclic 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 dehydroge...Cyclic 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 3.9Åresolution 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.展开更多
基金The project was funded by the Strategic Priority Research Program of the CAS(XDB27020106)the National Natural Science Foundation of China(31930064,31970264,31770778)+3 种基金the CAS Project for Young Scientists in Basic Research(#YSBR-015)the National Key R&D Program of China(2017YFA0503702)R.B.and L.D.thank the University of Verona(grant RIBA 2017 to R.B.)MUR(grant PRIN 2018 to L.D.)for financial support.X.S.,D.C.and X.P.are sponsored by the Youth Innovation Promotion Association at the Chinese Academy of Sciences(2018123,2018124 and 2018128).
文摘Cyclic 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 3.9Åresolution 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.
