Thousands of nuclear-encoded proteins are transported into chloroplasts through the TOC–TIC translocon that spans the chloroplast envelope membranes.A motor complex pulls the translocated proteins out of the TOC–TIC...Thousands of nuclear-encoded proteins are transported into chloroplasts through the TOC–TIC translocon that spans the chloroplast envelope membranes.A motor complex pulls the translocated proteins out of the TOC–TIC complex into the chloroplast stroma by hydrolyzing ATP.The Orf2971–FtsHi complex has been suggested to serve as the ATP-hydrolyzing motor in Chlamydomonas reinhardtii,but little is known about its architecture and assembly.Here,we report the 3.2-Åresolution structure of the Chlamydomonas Orf2971–FtsHi complex.The 20-subunit complex spans the chloroplast inner envelope,with two bulky modules protruding into the intermembrane space and stromal matrix.Six subunits form a hetero-hexamer that potentially provides the pulling force through ATP hydrolysis.The remaining subunits,including potential enzymes/chaperones,likely facilitate the complex assembly and regulate its proper function.Taken together,our results provide the structural foundation for a mechanistic understanding of chloroplast protein translocation.展开更多
The purified thermophilic bacterium PS3 F1β10×His-tag is inserted into the F0F1-ATP synthases of chromatophores isolated from photosynthetic bacteria Rhodospirillum rubrum. The studies of biochemical properties ...The purified thermophilic bacterium PS3 F1β10×His-tag is inserted into the F0F1-ATP synthases of chromatophores isolated from photosynthetic bacteria Rhodospirillum rubrum. The studies of biochemical properties of the hybrid chromatophores show that they have both protons-driving capability and photophosphorylation. The fluorescent actin filaments, as a marker of its orientation by video-microscopic experiment, are connected via Maleimido-C3-NTA to the reconstituted β10×His-tag of F0F1-ATP synthases.The clockwise rotation of FoFt-ATP synthases driven by light is observed directly when viewed from the Fo side to Ft. This system should be valuable for further studying the coupling property of F0F1-ATP synthase.展开更多
基金funded by the Strategic Priority Research Program of CAS(XDB37020101)the National Key R&D Program of China(2021YFA0910800)+3 种基金the National Natural Science Foundation of China(31930064)the Youth Innovation Promotion Association,Chinese Academy of Sciences(Y2022038)the Regional Joint Key Projects of the National Foundation of China(U22A20445)the Natural Science Foundation of Shandong Province(ZR2023ZD30).
文摘Thousands of nuclear-encoded proteins are transported into chloroplasts through the TOC–TIC translocon that spans the chloroplast envelope membranes.A motor complex pulls the translocated proteins out of the TOC–TIC complex into the chloroplast stroma by hydrolyzing ATP.The Orf2971–FtsHi complex has been suggested to serve as the ATP-hydrolyzing motor in Chlamydomonas reinhardtii,but little is known about its architecture and assembly.Here,we report the 3.2-Åresolution structure of the Chlamydomonas Orf2971–FtsHi complex.The 20-subunit complex spans the chloroplast inner envelope,with two bulky modules protruding into the intermembrane space and stromal matrix.Six subunits form a hetero-hexamer that potentially provides the pulling force through ATP hydrolysis.The remaining subunits,including potential enzymes/chaperones,likely facilitate the complex assembly and regulate its proper function.Taken together,our results provide the structural foundation for a mechanistic understanding of chloroplast protein translocation.
文摘The purified thermophilic bacterium PS3 F1β10×His-tag is inserted into the F0F1-ATP synthases of chromatophores isolated from photosynthetic bacteria Rhodospirillum rubrum. The studies of biochemical properties of the hybrid chromatophores show that they have both protons-driving capability and photophosphorylation. The fluorescent actin filaments, as a marker of its orientation by video-microscopic experiment, are connected via Maleimido-C3-NTA to the reconstituted β10×His-tag of F0F1-ATP synthases.The clockwise rotation of FoFt-ATP synthases driven by light is observed directly when viewed from the Fo side to Ft. This system should be valuable for further studying the coupling property of F0F1-ATP synthase.
