Reprogramming encapsulins into modular carbon-fixing nanocompartments

Area of Science:

• Synthetic biology
• Plant science
• Biochemistry

Background:

• Enhancing C3 crop photosynthesis via carbon-concentrating mechanisms (CCMs) is crucial for increasing yields.
• Previous attempts to engineer CCMs using algal pyrenoids or cyanobacterial carboxysomes faced challenges due to complex genetic requirements and protein specificity.

Purpose of the Study:

• To develop a streamlined, modular synthetic system for creating functional carboxysome mimics in plants.
• To establish a foundation for engineering improved photosynthetic efficiency in crops.

Main Methods:

• Utilized encapsulin nanocompartments (QtEnc) from Quasibacillus thermotolerans as a chassis for synthetic carboxysomes.
• Engineered a cargo-loading peptide to facilitate targeted encapsulation of diverse Rubisco isoforms within QtEnc.
• Assessed the CO2-fixing activity of encapsulated Rubisco.

Main Results:

• Successfully demonstrated targeted encapsulation of various Rubisco isoforms within QtEnc nanocompartments.
• Confirmed that encapsulated Rubisco retained significant CO2-fixing activity.
• Developed an isoform-agnostic system for creating synthetic carboxysome mimics.

Conclusions:

• The developed synthetic encapsulin system provides a simpler and more tractable approach for engineering CCMs in plants compared to native structures.
• This modular system lays the groundwork for future integration of carbonic anhydrase and further optimization of synthetic CCMs in crops.