Complexes of the Outer Mitochondrial Membrane Protein MitoNEET with Resveratrol-3-Sulfate

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• 作者：Waqar Arif ; Shu Xu ; Dragan Isailovic ; Werner J. Geldenhuys ; Richard T. Carroll ; Max O. Funk ; Jr.
• 刊名：Biochemistry
• 出版年：2011
• 出版时间：June 28, 2011
• 年：2011
• 卷：50
• 期：25
• 页码：5806-5811
• 全文大小：786K
• 年卷期：v.50,no.25(June 28, 2011)
• ISSN：1520-4995

文摘

Binding of the thiazolidinedione antidiabetic drug pioglitazone led to the discovery of a novel outer mitochondrial membrane protein of unknown function called mitoNEET. The protein is homodimeric and contains a uniquely ligated two iron鈥搕wo sulfur cluster in each of its two cytosolic domains. Electrospray ionization mass spectrometry was employed to characterize solutions of the soluble cytosolic domain (amino acids 32鈥?08) of the protein. Ions characteristic of dimers containing the cofactors were readily detected under native conditions. mitoNEET responded to exposure to solutions at low pH by dissociation to give monomers that retained the cofactor, followed by dissociation of the cofactor in a concerted fashion. mitoNEET formed complexes with resveratrol-3-sulfate, one of the primary metabolites of the natural product resveratrol. Resveratrol itself showed no tendency to interact with mitoNEET. The formation of complexes was evident in both electrospray ionization mass spectrometry and isothermal titration calorimetry measurements. Up to eight molecules of the compound associated with the dimeric form of the protein in a sequential fashion. Dissociation constants determined by micorcalorimetry were in the range 5鈥?6 渭M for the various binding sites. The only other known naturally occurring binding partner for mitoNEET at present is NADPH. It is very interesting that the iron鈥搒ulfur cluster containing protein interacts with two potentially redox active substances at the surface of mitochondria. These findings provide a new direction for research into two poorly understood, yet biomedically relevant, species.