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

Abstract

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.

Recent Advances in Engineering Heterotrophic Microorganisms for Reinforcing CO2 Fixation Based on Calvin–Benson–Bassham Cycle

“…The highly active form II RuBisCO from Riftia pachyptila (RPE RuBisCO) has a simple hexameric structure and shows a high activity of carboxylation. The straightforward expression and assembly of this enzyme in heterologous systems make the RPE RuBisCO an ideal enzyme for CO 2 capture . These studies lay the groundwork for engineering the CBB cycle in model heterotrophic microorganisms.…”

“…The straightforward expression and assembly of this enzyme in heterologous systems make the RPE RuBisCO an ideal enzyme for CO 2 capture. 38 These studies lay the groundwork for engineering the CBB cycle in model heterotrophic microorganisms.…”

Engineering Rubisco to enhance CO2 utilization

“…Through directed evolution of M. burtonii Rubisco in E. coli , it has been confirmed that the evolved E138V and K332E mutant enzymes exhibit significantly improved CO 2 -fixation speed, CO 2 -affinity, and specificity for CO 2 [ 127 ]. As more highly active Forms II and III of Rubisco have been discovered [ 10 , 28 , 128 ], it suggests that these forms, facing different evolutionary pressures from Form I, may be less conservative and hold greater evolutionary potential. Consequently, the ongoing directed evolution of Forms II and III Rubisco opens up new possibilities for enhancing leaf photosynthesis and promoting plant growth.…”