1. Structural characterization of a plant photosystem I and NAD(P)H dehydrogenase supercomplex.
- Author
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Kouřil R, Strouhal O, Nosek L, Lenobel R, Chamrád I, Boekema EJ, Šebela M, and Ilík P
- Subjects
- Electron Transport, Ferredoxins metabolism, Hordeum chemistry, Hordeum radiation effects, Light, Light-Harvesting Protein Complexes isolation & purification, Light-Harvesting Protein Complexes metabolism, Microscopy, Electron, Models, Molecular, NAD metabolism, NADPH Dehydrogenase isolation & purification, NADPH Dehydrogenase metabolism, Native Polyacrylamide Gel Electrophoresis, Oxidation-Reduction, Photosystem I Protein Complex isolation & purification, Photosystem I Protein Complex metabolism, Plant Leaves chemistry, Plant Leaves enzymology, Plant Leaves radiation effects, Thylakoids metabolism, Hordeum enzymology, Light-Harvesting Protein Complexes chemistry, NADPH Dehydrogenase chemistry, Photosystem I Protein Complex chemistry
- Abstract
Cyclic electron transport (CET) around photosystem I (PSI) plays an important role in balancing the ATP/NADPH ratio and the photoprotection of plants. The NAD(P)H dehydrogenase complex (NDH) has a key function in one of the CET pathways. Current knowledge indicates that, in order to fulfill its role in CET, the NDH complex needs to be associated with PSI; however, until now there has been no direct structural information about such a supercomplex. Here we present structural data obtained for a plant PSI-NDH supercomplex. Electron microscopy analysis revealed that in this supercomplex two copies of PSI are attached to one NDH complex. A constructed pseudo-atomic model indicates asymmetric binding of two PSI complexes to NDH and suggests that the low-abundant Lhca5 and Lhca6 subunits mediate the binding of one of the PSI complexes to NDH. On the basis of our structural data, we propose a model of electron transport in the PSI-NDH supercomplex in which the association of PSI to NDH seems to be important for efficient trapping of reduced ferredoxin by NDH., (© 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.)
- Published
- 2014
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