Multi-omic dynamics associate oxygenic photosynthesis with nitrogenase-mediated h 2 production in cyanothece sp. ATCC 51142

Abstract

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.