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Redox‐dependent structural changes in archaeal and bacterial Rieske‐type [2Fe‐2S] clusters

2002; Wiley; Volume: 11; Issue: 12 Linguagem: Inglês

10.1110/ps.0222402

1469-896X

Nathaniel J. Cosper, D. Matthew Eby, Asako Kounosu, Norio Kurosawa, Ellen L. Neidle, Donald M. Kurtz, Toshio Iwasaki, Robert A. Scott,

Porphyrin Metabolism and Disorders

Proteins containing Rieske-type [2Fe-2S] clusters play important roles in many biological electron transfer reactions. Typically, [2Fe-2S] clusters are not directly involved in the catalytic transformation of substrate, but rather supply electrons to the active site. We report herein X-ray absorption spectroscopic (XAS) data that directly demonstrate an average increase in the iron-histidine bond length of at least 0.1 A upon reduction of two distantly related Rieske-type clusters in archaeal Rieske ferredoxin from Sulfolobus solfataricus strain P-1 and bacterial anthranilate dioxygenases from Acinetobacter sp. strain ADP1. This localized redox-dependent structural change may fine tune the protein-protein interaction (in the case of ARF) or the interdomain interaction (in AntDO) to facilitate rapid electron transfer between a lower potential Rieske-type cluster and its redox partners, thereby regulating overall oxygenase reactions in the cells.