Background: Rubisco, a key photosynthetic enzyme of eight large and eight small subunits, is phylogenetically divided into green and red types. Results: The small subunits of red-type Rubisco contain a C-terminal ␤-hairpin extension that mediates efficient assembly of the holoenzyme. Conclusion: The C-terminal ␤-hairpin renders red-type Rubisco independent of specialized assembly chaperones. Significance: These findings can help in bioengineering red-type Rubisco into crop plants.