Biology Newsfeed

[Report] Light-driven dinitrogen reduction catalyzed by a CdS:nitrogenase MoFe protein biohybrid

ScienceNOW - Fetched: April 21st, 2016, 3:00pm UTC

The splitting of dinitrogen (N2) and reduction to ammonia (NH3) is a kinetically complex and energetically challenging multistep reaction. In the Haber-Bosch process, N2 reduction is accomplished at high temperature and pressure, whereas N2 fixation by the enzyme nitrogenase occurs under ambient conditions using chemical energy from adenosine 5′-triphosphate (ATP) hydrolysis. We show that cadmium sulfide (CdS) nanocrystals can be used to photosensitize the nitrogenase molybdenum-iron (MoFe) protein, where light harvesting replaces ATP hydrolysis to drive the enzymatic reduction of N2 into NH3. The turnover rate was 75 per minute, 63% of the ATP-coupled reaction rate for the nitrogenase complex under optimal conditions. Inhibitors of nitrogenase (i.e., acetylene, carbon monoxide, and dihydrogen) suppressed N2 reduction. The CdS:MoFe protein biohybrids provide a photochemical model for achieving light-driven N2 reduction to NH3. Authors: Katherine A. Brown, Derek F. Harris, Molly B. Wilker, Andrew Rasmussen, Nimesh Khadka, Hayden Hamby, Stephen Keable, Gordana Dukovic, John W. Peters, Lance C. Seefeldt, Paul W. King

Read more

Return to the Newsfeed