Archaeal Nitrogenase Structure Reveals Energy-Linked Inhibition Mechanism
Researchers have determined the first cryo-electron microscopy structure of a native nitrogenase-PII protein supercomplex from the methanogen Methanosarcina acetivorans. The study reveals that six PII complexes bridge three NifDK heterotetramers, sterically blocking the enzyme and locking it in an inactive state. This architecture links nitrogenase activity directly to cellular energy and nitrogen status through asymmetric binding of ADP and 2-oxoglutarate.