Resonance Raman studies of the [4Fe‐4S] to [2Fe‐2S] cluster conversion in the iron protein of nitrogenase

FEBS Letters

Fu, Weiguang¹  Johnson, Michael K.¹  Morgan, T.Vance¹  Mortenson, Leonard E.¹ 

[1] Center for Metalloenzyme Studies and School of Chemical Sciences, University of Georgia, Athens, GA 30602, USA

关键词: Nitrogenase;    Iron protein;    Resonance Raman;    Iron-sulfur cluster;   

DOI  :  10.1016/0014-5793(91)80676-T

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Resonance Raman spectroscopy has been used to investigate the Fe-S stretching modes of the [4Fe-4S]²⁺ cluster in the oxidized iron protein of Clostridium pasteurianum nitrogenase. The results are consistent with a cubane [4Fe-4S] cluster having effective T_d symmetry with cysteinyl coordination for each iron. In accord with previous optical and EPR studies [(1984) Biochemistry 23, 2118–2122], treatment with the iron chelator α,α′-dipyridyl in the presence of MgATP is shown to effect cluster conversion to a [2Fe-2S]²⁺ cluster. Resonance Raman data also indicate that partial conversion to a [2Fe-2S]²⁺ cluster is induced by thionine-oxidation in the presence of MgATP in the absence of an iron chelator. This result suggests new explanations for the dramatic change in the CD spectrum that accompanies MgATP-binding to the oxidized Fe protein and the anomalous resonance Raman spectra of thionine-oxidized Clostridium pasteurianum bidirectional hydrogenase.

【 授权许可】

Unknown