Novel Bacterial Clade Reveals Origin of Form I Rubisco

The Science

• All plant biomass is sourced from the carbon-fixing enzyme Rubisco.
• Although there is significant interest in engineering Rubisco to improve overall plant productivity, there has been little progress in the field.
• All plants contain Form I Rubisco, and all Form I Rubisco consist of both eight Large (RbcL) and eight Small (RbcS) subunits. No Form I Rubisco has previously been discovered to lack the small subunit, which would represent a key transition in Rubisco evolution.
• Understanding how Rubisco evolved may provide unique insight into engineering Rubisco.

The Impact

• Structural insight into how Form I Rubisco evolved will provide the basis for engineering Rubisco in bioenergy crops.
• Demonstration of the utility of metagenomics to discover novel families of enzymes.

Summary

• Used metagenomics to discover a previously uncharacterized clade of Rubisco that is the sister clade to Form I Rubisco, that the researchers named Form I’.
• Synthesized, expressed, purified, and biochemically characterized the novel enzyme.
• Solved solution state and crystal structure of novel Form I’ Rubisco.

Principal Investigator(s)

Patrick Shih
Lawrence Berkeley National Laboratory

Jill Banfield
University of California, Berkeley

References

Banda, D.M. et al. “Novel bacterial clade reveals origin of form I Rubisco.” Nature Plants 6, 1158–1166 (2020). [DOI:10.1038/s41477-020-00762-4]