Carboxysome encapsulation of the CO₂-fixing enzyme Rubisco in tobacco chloroplasts
Date
2018
Authors
Long, Benedict
Hee, Wei Yih
Sharwood, Robert
Rae, Benjamin
Kaines, Sarah
Lim, Yi Leen
Nguyen, Nghiem Dinh
Massey, Baxter
Bala, Soumi
von Caemmerer, Susanne
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Nature Research
Abstract
A long-term strategy to enhance global crop photosynthesis and yield involves the introduction of cyanobacterial CO2-concentrating mechanisms (CCMs) into plant chloroplasts. Cyanobacterial CCMs enable relatively rapid CO2 fixation by elevating intracellular inorganic carbon as bicarbonate, then concentrating it as CO2 around the enzyme Rubisco in specialized protein micro-compartments called carboxysomes. To date, chloroplastic expression of carboxysomes has been elusive, requiring coordinated expression of almost a dozen proteins. Here we successfully produce simplified carboxysomes, isometric with those of the source organism Cyanobium, within tobacco chloroplasts. We replace the endogenous Rubisco large subunit gene with cyanobacterial Form-1A Rubisco large and small subunit genes, along with genes for two key α-carboxysome structural proteins. This minimal gene set produces carboxysomes, which encapsulate the introduced Rubisco and enable autotrophic growth at elevated CO2. This result demonstrates the formation of α-carboxysomes from a reduced gene set, informing the step-wise construction of fully functional α-carboxysomes in chloroplasts.
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Nature Communications
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Journal article
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Open Access
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Creative Commons Attribution 4.0 International License
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