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Lil3 Assembles with Proteins Regulating Chlorophyll Synthesis in Barley
Astrid Mork-Jansson1, Ann Kristin Bue1, Daniela Gargano1
1Center for Organelle Research, University of Stavanger, Stavanger, Norway.
Plos One
|July 15, 2015
Summary
Light-harvesting-like (LIL) proteins, like Lil3, assemble with chlorophyll synthesis enzymes in barley etioplasts. This assembly is regulated by light and chlorophyllide, impacting plant light responses.
Area of Science:
- Plant Biology
- Molecular Biology
- Biochemistry
Background:
- Light-harvesting-like (LIL) proteins are membrane proteins sharing motifs with major light-harvesting antenna proteins.
- LIL proteins are implicated in tetrapyrrole biosynthesis regulation and plant light-stress responses.
Purpose of the Study:
- To investigate the assembly of Lil3 protein with other proteins in response to light and chlorophyll precursors.
- To elucidate the role of Lil3 in chlorophyll biosynthesis and etioplast development.
Main Methods:
- Native PAGE to analyze protein complex assembly.
- Split ubiquitin assay to confirm protein interactions.
- Fluorescence spectroscopy to identify chlorophyll-related compounds.
Main Results:
- Chlorophyllide and geranylgeraniolpyrophosphate trigger Lil3 assembly into distinct fluorescent bands (F1, F2, F3).
- Light and chlorophyllide induce accumulation of protochlorophyllide-oxidoreductase and chlorophyll synthase in band F3.
- Geranylgeraniolpyrophosphate causes loss of F3 and accumulation of geranylgeranyl reductase in F1/F2, with chlorophyll esterified to phytol.
- Chlorophyll esterified to phytol, psbD, psb29, and APX accumulate in band F2.
Conclusions:
- Lil3 assembles with proteins involved in chlorophyll synthesis within barley etioplasts.
- This assembly process is dynamically regulated by light and specific molecular intermediates.
- The findings provide insights into the coordination of chlorophyll biosynthesis and light-harvesting complex assembly.
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