일시: 9/30(목) 17시10분
연사: 강원철 (숭실대학교 화학과) Wonchull Kang (Department of Chemistry, Soongsil University)
제목:Structural basis for the synthesis of the nitrogenase cofactor by NifB, a radical SAM enzyme
내용:
Nitrogenase, uniquely responsible for replenishing the nitrogen cycle from atmospheric dinitrogen, catalyzes the ATP–dependent reduction of N2 to ammonia at ambient temperature and pressure. Its active site contains the P–cluster and the iron–molybdenum cofactor (FeMo-co). The former is a [Fe8S7] center responsible for delivering electrons to the latter, a [MoFe7S9C–(R)–homocitrate] species, where N2 reduction takes place. NifB, a radical S–adenosyl–L–methionine (SAM) enzyme, plays a key role in FeMo-co assembly as it catalyzes the fusion of two [Fe4S4] clusters and the insertion of carbide and sulfide ions. Two crystal structures reported recently lays the groundwork for unravelling the intricate mechanism of radical SAM dependent carbide insertion during the process of nitrogenase cofactor assembly. Here, I’ll introduce to radical SAM enzyme and the one example, NifB.