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.

• MeSH
• elektronová mikroskopie MeSH
• ferredoxiny metabolismus   MeSH
• fotosystém I - proteinový komplex chemie   izolace a purifikace   metabolismus   MeSH
• ječmen (rod) chemie   enzymologie   účinky záření   MeSH
• listy rostlin chemie   enzymologie   účinky záření   MeSH
• molekulární modely MeSH
• NAD metabolismus   MeSH
• NADPH-dehydrogenasa chemie   izolace a purifikace   metabolismus   MeSH
• nativní elektroforéza na polyakrylamidovém gelu MeSH
• oxidace-redukce MeSH
• světlo MeSH
• světlosběrné proteinové komplexy chemie   izolace a purifikace   metabolismus   MeSH
• transport elektronů MeSH
• tylakoidy metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH