Two-cell metabolism in multicellular cyanobacteria ($)

Nitrogen-fixing cyanobacteria such as Anabaena sp. PCC 7120 have the challenge of supporting nitrogenase, an enzyme that is highly sensitive to oxygen, and simultaneously photosynthesis, an oxygen-producing set of reactions. They accomplish this by segregating these reactions into two cells, heterocysts and vegetative cells. Malatinszky et al. curate and compile a stoichiometric model of the flow of metabolites, electrons and fixed nitrogen between the two cells. The model indicates that at least four exchange metabolites are needed for optimal growth and provides a platform for further metabolic engineering studies of multicellular cyanobacteria. Plant Physiol. 10.1104/pp.16.01487