Inhaltszusammenfassung

Light-harvesting chlorophyll alb-binding protein, LHCP, or its precursor, pLHCP, cannot be stably inserted into barley etioplast membranes in vitro. However, when these etioplast membranes are supplemented with the chlorophyll analogs Zn-pheophytin a/b, synthesized in situ from Zn-pheophorbide a/b and digeranyl pyrophosphate, pLHCP is inserted into a protease-resistant state, This proves that chlorophyll is the only component lacking in etioplast membranes that is necessary for stable LHCP in...Light-harvesting chlorophyll alb-binding protein, LHCP, or its precursor, pLHCP, cannot be stably inserted into barley etioplast membranes in vitro. However, when these etioplast membranes are supplemented with the chlorophyll analogs Zn-pheophytin a/b, synthesized in situ from Zn-pheophorbide a/b and digeranyl pyrophosphate, pLHCP is inserted into a protease-resistant state, This proves that chlorophyll is the only component lacking in etioplast membranes that is necessary for stable LHCP insertion, Synthesis of Zn-pheophytin b alone promotes insertion of LHCP in. vitro into a protease-resistant state, whereas synthesis of Zn-pheophytin a alone does not, Insertion of pLHCP into etioplast membranes can also be stimulated by adding chlorophyll a and chlorophyll b to the membranes, albeit at a significantly lower efficiency as compared with Zn-pheophytin a/b synthesized in situ, When pLHCP is inserted into chlorophyll-or Zn-pheophytin-supplemented etioplast membranes and then assayed with protease, only the protease digestion product indicative of the monomeric major light-harvesting chlorophyll a/b complex (LHCII) is found but not the one indicating trimeric complexes, In this respect, chlorophyll-or Zn-pheophytin-supplemented etioplast membranes resemble thylakoid membranes at an early greening stage: pLHCP inserted into plastid membranes from greening barley is assembled into trimeric LHCII only after more than 1 h of greening.» weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
Pflanzenwissenschaften

DDC Sachgruppe:
Pflanzen (Botanik)