Rubisco: The Enzyme that Keeps on Giving

In cyanobacteria, the RbcX protein enhances the production of Rubisco, the multisubunit enzyme that catalyzes the first step of carbon dioxide fixation in most autotrophic organisms. In this issue of Cell, report that RbcX acts as a specific assembly chaperone that mobilizes the large subunits of Rubisco to a specific oligomeric core that can then combine with the small subunits of Rubisco to form the functional holoenzyme.