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Interplay between differentially expressed enzymes contributes to light color acclimation in marine Synechococcus

TitleInterplay between differentially expressed enzymes contributes to light color acclimation in marine Synechococcus
Publication TypeJournal Article
Year of Publication2019
AuthorsSanfilippo JE, Nguyen AA, Garczarek L, Karty JA, Pokhrel S, Strnat JA, Partensky F, Schluchter WM, Kehoe DM
JournalProceedings of the National Academy of Sciences
Volume116
Pagination6457–6462
Date Publishedmar
ISSN0027-8424
KeywordsRCC1086, RCC2035, rcc2380, rcc2382, RCC2385, RCC2433, RCC2437, RCC2528, RCC2533, RCC2534, RCC2535, RCC2571, RCC2673, RCC28, RCC307, RCC328, RCC515, rcc555, rcc791
Abstract

Marine Synechococcus , a globally important group of cyanobacteria, thrives in various light niches in part due to its varied photosynthetic light-harvesting pigments. Many Synechococcus strains use a process known as chromatic acclimation to optimize the ratio of two chromophores, green-light–absorbing phycoerythrobilin (PEB) and blue-light–absorbing phycourobilin (PUB), within their light-harvesting complexes. A full mechanistic understanding of how Synechococcus cells tune their PEB to PUB ratio during chromatic acclimation has not yet been obtained. Here, we show that interplay between two enzymes named MpeY and MpeZ controls differential PEB and PUB covalent attachment to the same cysteine residue. MpeY attaches PEB to the light-harvesting protein MpeA in green light, while MpeZ attaches PUB to MpeA in blue light. We demonstrate that the ratio of mpeY to mpeZ mRNA determines if PEB or PUB is attached. Additionally, strains encoding only MpeY or MpeZ do not acclimate. Examination of strains of Synechococcus isolated from across the globe indicates that the interplay between MpeY and MpeZ uncovered here is a critical feature of chromatic acclimation for marine Synechococcus worldwide.

URLhttp://www.pnas.org/lookup/doi/10.1073/pnas.1810491116
DOI10.1073/pnas.1810491116