Functional Implications of Photosystem II Crystal Formation in Photosynthetic Membranes

Stefanie Tietz, Sujith Puthiyaveetil, Heather M Enlow, Robert Yarbrough, Magnus Wood, Dmitry A Semchonok, Troy Lowry, Zhirong Li, Peter Jahns, Egbert J Boekema, Steven Lenhert, Krishna K Niyogi, Helmut Kirchhoff

Research output: Contribution to journalArticleAcademicpeer-review

27 Citations (Scopus)

Abstract

The structural organization of proteins in biological membranes can affect their function. Photosynthetic thylakoid membranes in chloroplasts have the remarkable ability to change their supramolecular organization between disordered and semicrystalline states. Although the change to the semicrystalline state is known to be triggered by abiotic factors, the functional significance of this protein organization has not yet been understood. Taking advantage of an Arabidopsis thaliana fatty acid desaturase mutant (fad5) that constitutively forms semicrystalline arrays, we systematically test the functional implications of protein crystals in photosynthetic membranes. Here we show that the change into an ordered state facilitates molecular diffusion of photosynthetic components in crowded thylakoid membranes. The increased mobility of small lipophilic molecules like plastoquinone and xanthophylls has implications for diffusion-dependent electron transport and photoprotective energy-dependent quenching. The mobility of the large photosystem II supercomplexes, on the other hand, is impaired, leading to retarded repair of damaged proteins. Our results demonstrate that supramolecular changes into more ordered states have differing impacts on photosynthesis that favor either diffusion-dependent electron transport and photoprotection or protein repair processes, thus fine-tuning the photosynthetic energy conversion.

Original languageEnglish
Pages (from-to)14091-14106
Number of pages16
JournalThe Journal of Biological Chemistry
Volume290
Issue number22
DOIs
Publication statusPublished - 20-Apr-2015

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