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Title: The structural and functional domains of plant thylakoid membranes
Summary

In plants, the stacking of part of the photosynthetic thylakoid membrane generates two main subcompartments: the stacked grana core and unstacked stroma lamellae. However, a third distinct domain, the grana margin, has been postulated but its structural and functional identity remains elusive. Here, an optimized thylakoid fragmentation procedure combined with detailed ultrastructural, biochemical, and functional analyses reveals the distinct composition of grana margins. It is enriched with lipids, cytochromeb6fcomplex, andATPase while depleted in photosystems and light‐harvesting complexes. A quantitative method is introduced that is based on Blue Native Polyacrylamide Gel Electrophoresis (BNPAGE) and dot immunoblotting for quantifying various photosystemII(PSII) assembly forms in different thylakoid subcompartments. The results indicate that the grana margin functions as a degradation and disassembly zone for photodamagedPSII. In contrast, the stacked grana core region contains fully assembled and functionalPSIIholocomplexes. The stroma lamellae, finally, contain monomericPSIIas well as a significant fraction of dimeric holocomplexes that identify this membrane area as thePSIIrepair zone. This structural organization and the heterogeneousPSIIdistribution support the idea that the stacking of thylakoid membranes leads to a division of labor that establishes distinct membrane areas with specific functions.

 
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NSF-PAR ID:
10079227
Author(s) / Creator(s):
 ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
The Plant Journal
Volume:
97
Issue:
3
ISSN:
0960-7412
Page Range / eLocation ID:
p. 412-429
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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