Adrenodoxin reductase-adrenodoxin complex structure suggests electron transfer path in steroid biosynthesis

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Item Type:	Article
Title:	Adrenodoxin reductase-adrenodoxin complex structure suggests electron transfer path in steroid biosynthesis
Creators Name:	Mueller, J.J., Lapko, A., Bourenkov, G., Ruckpaul, K. and Heinemann, U.
Abstract:	The steroid hydroxylating system of adrenal cortex mitochondria consists of the membrane-attached NADPH-dependent adrenodoxin reductase (AR), the soluble one-electron transport protein adrenodoxin (Adx), and a membrane-integrated cytochrome P450 of the CYP11 family. In the 2.3-Å resolution crystal structure of the Adx-AR complex, 580 Å2 of partly polar surface are buried. Main interaction sites are centered around Asp79, Asp76, Asp72, and Asp39 and around Arg211, Arg240, Arg244, and Lys 27 of AR, respectively. In particular, the region around Asp 39 defines a new protein interaction site for Adx, similar to those found in plant and bacterial ferredoxins. Additional contacts involve the electron transfer region between the redox centers of AR and Adx and C-terminal residues of Adx. The Adx residues Asp113 to Arg115 adopt 310-helical conformation and engage in loose intermolecular contacts within a deep cleft of AR. Complex formation is accompanied by a slight domain rearrangement in AR. The [2Fe-2S] cluster of Adx and the isoalloxazine rings of FAD of AR are 10 Å apart suggesting a possible electron transfer route between these redox centers. The AR-Adx complex represents the first structure of a biologically relevant complex between a ferredoxin and its reductase.
Keywords:	Adrenodoxin, Binding Sites, Electron Transport, Electrostatics, Ferredoxin-NADP Reductase, Flavin-Adenine Dinucleotide, Molecular Models, Protein Binding, Recombinant Proteins, Recombinant Proteins, Animals, Cattle
Source:	Journal of Biological Chemistry
ISSN:	0021-9258
Publisher:	American Society for Biochemistry and Molecular Biology
Volume:	276
Number:	4
Page Range:	2786-2789
Date:	1 January 2001
Official Publication:	https://doi.org/10.1074/jbc.M008501200
PubMed:	View item in PubMed

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