Background

Carbon dioxide (CO₂) is an atmospheric greenhouse gas that feeds all life on earth and plays a critical role in global warming. At the same time, readily available CO₂ constitutes an inexpensive carbon source for future sustainable industries. Synthetic chemistry lacks suitable catalysts to functionalize carbon dioxide in mild reaction conditions, so there is increasing interest in exploiting the CO₂-fixation mechanisms offered by nature. 

Project

In this exchange proposal we will undertake fast time-resolved structural-dynamics studies of one of the fastest CO2-fixation enzymes, enoyl-CoA carboxylase/reductase (ECR). For this we will use ambient temperature serial X-ray crystallography on the new EMBL-ESRF Joint Structural Biology Group Beamline ID29 at the ESRF, which can achieve up to 10μs resolution, and fluorescence lifetime imaging microscopy (FLIM) at Stanford/SLAC. ECR achieves its fast CO2-fixation by coupling between 4 subunits, and serial X-ray crystallography at ID29 will provide important insights into this as well as the capture and posing of the NADPH cofactor and substrates, CO2 and enoyl-CoA, for C-C bond forming reactions and their rapid release. FLIM will assess reaction progression by monitoring NADPH fluorescence lifetime dynamics. The two experiments complement each other by correlating the structural and functional states of the enzyme during fixation. The knowledge gained will pave the way for faster biomolecule productions using engineered C-cycling enzymes.

This project is supported by an exchange grant, awarded to Rose Knight

References:

DeMirci, H., Rao, Y., Stoffel, G. M. et al. (2022) Intersubunit Coupling Enables Fast CO₂-Fixation by Reductive Carboxylases. ACS Cent. Sci. 8, 1091-1101.