Jan Michael Schuller’s research has produced fresh insights into fundamental biological mechanisms in various fields of structural biology, biophysics and biochemistry. In this way, Schuller has contributed significantly to a deeper understanding of the function of photosynthetic complexes in cyanobacteria, which is also relevant with regard to aspects of practical application. With his DFG-funded Emmy Noether Junior Research Group, Schuller is investigating the structure of enzymes involved in carbon fixation and the carbon concentration mechanism in cyanobacteria. Cyanobacteria are photosynthetic bacteria that make up a high proportion of marine phytoplankton, for example. Using these organisms, Schuller was able to show the way in which carbon concentration is affected by the interplay between the enzyme RuBisCO, which is responsible for fixing CO2 from the atmosphere, and a carbonic anhydrase that provides CO2 replenishment. The elucidation of this mechanism was made possible by Schuller’s innovative structural biological methods, such as the application of cryoelectron microscopy at the single-molecule level.