Nitrogenase: standing at the crossroads

Nitrogenase catalyzes the ATP-dependent reduction of dinitrogen to ammonia, which is central to the process of biological nitrogen fixation. Recent pr ogress towards establishing the mechanism of action of this complex metallo enzyme reflects the contributions of a combination of structural, biochemic al, spectroscopic, synthetic and theoretical approaches to a challenging pr oblem with implications for a range of biochemical and chemical systems.