Multi-Omic Dynamics Associate Oxygenic Photosynthesis with Nitrogenase-Mediated H(2) Production in Cyanothece sp. ATCC 51142

To date, the proposed mechanisms of nitrogenase-driven photosynthetic H(2) production by the diazotrophic unicellular cyanobacterium Cyanothece sp. ATCC 51142 have assumed that reductant and ATP requirements are derived solely from glycogen oxidation and cyclic-electron flow around photosystem I. Through genome-scale transcript and protein profiling, this study presents and tests a new hypothesis on the metabolic relationship between oxygenic photosynthesis and nitrogenase-mediated H(2) production in Cyanothece 51142. Our results show that net-positive rates of oxygenic photosynthesis and increased expression of photosystem II reaction centers correspond and are synchronized with nitrogenase expression and H(2) production. These findings provide a new and more complete view on the metabolic processes contributing to the energy budget of photosynthetic H(2) production and highlight the role of concurrent photocatalytic H(2)O oxidation as a participating process.