固氮酶反应中铁蛋白与MgATP配位的化学模拟

Chemical Modeling of Complexation of Fe-Protein with MgATP in Nitrogenase Reactions

以[Fe_4S_4(SCH_2Ph)_4]^(-2)作为氧化态铁蛋白4Fe-4S中心的模型化合物,化学模拟研究表明,ATP能与[Fe_4S_4(SCH_2Ph)_4]^(-2)原子簇结合,促进原子簇与亚甲蓝之间的氧化还原反应速率,并敏化原子簇中的Fe(Ⅱ),使其易与亚铁螯合剂反应,用正庚烧作萃取刑,在原子簇-ATP体系没有检测到游离的HSCH_2Ph,ATP没有置换原子簇中的—SCH_2Ph,这表明作为电子活化剂的ATP可能通过其磷酸根与Fe_4S_4原子簇结合。

Chemical-modeling studies show that ATP can complex with [ Fe4S4 (SCH2Ph)4]-2 cluster which as a model compound of the 4Fe-4S center of the oxidized Fe-protein,resulting in significant enhancement of redox reaction rates between [Fe4S4(SCHzPh)4]-2(Z=2,1) and methylene blue,in dramatic sensitization of [Fe4S4(SCHzPh)4]-2 to disruption by iron chelaters,as well as in no free HSCH2Ph could be detected with AgDz-CCl4 (dithiazon reagent) in the n-heptane extracts from [Fe4S4(SCH2Ph)4]-2 - ATP systems as addition ligand without displacing any of the thio-ligand. It indicates that ATP which serve as 'electron activator' were probably coordinated through the binding of their PO4 group to the cubane cluster.