Discovery of a readily heterologously expressed Rubisco from the deep sea with potential for CO₂ capture

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the key CO₂-fixing enzyme in photosynthesis, is notorious for its low carboxylation. We report a highly active and assembly-competent Form II Rubisco from the endosymbiont of a deep-sea tubeworm Riftia pachyptila (RPE Rubisco), which shows a 50.5% higher carboxylation efficiency than that of a high functioning Rubisco from Synechococcus sp. PCC7002 (7002 Rubisco). It is a simpler hexamer with three pairs of large subunit homodimers around a central threefold symmetry axis. Compared with 7002 Rubisco, it showed a 3.6-fold higher carbon capture efficiency in vivo using a designed CO₂ capture model. The simple structure, high carboxylation efficiency, easy heterologous soluble expression/assembly make RPE Rubisco a ready-to-deploy enzyme for CO₂ capture that does not require complex co-expression of chaperones. The chemosynthetic CO₂ fixation machinery of chemolithoautotrophs, CO₂-fixing endosymbionts, may be more efficient than previously realized with great potential for next-generation microbial CO₂ sequestration platforms.