文章基本信息

标题：In vivo iron–sulfur cluster formation
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作者：Estella C. Raulfs ; Ina P. O'Carroll ; Patricia C. Dos Santos 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2008
卷号：105
期号：25
页码：8591-8596
DOI：10.1073/pnas.0803173105
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：It has been proposed that iron-sulfur [Fe-S] clusters destined for the maturation of [Fe-S] proteins can be preassembled on a molecular scaffold designated IscU. In the present article, it is shown that production of the intact Azotobacter vinelandii [Fe-S] cluster biosynthetic machinery at levels exceeding the amount required for cellular maturation of [Fe-S] proteins results in the accumulation of: (i) apo-IscU, (ii) an oxygen-labile [2Fe-2S] cluster-loaded form of IscU, and (iii) IscU complexed with the S-delivery protein, IscS. It is suggested that these species represent different stages of the [Fe-S] cluster assembly process. Substitution of the IscU Asp39 residue by Ala results in the in vivo trapping of a stoichiometric, noncovalent, nondissociating IscU-IscS complex that contains an oxygen-resistant [Fe-S] species. In aggregate, these results validate the scaffold hypothesis for [Fe-S] cluster assembly and indicate that in vivo [Fe-S] cluster formation is a dynamic process that involves the reversible interaction of IscU and IscS.
关键词：Azotobacter ; Isc ; IscU ; scaffold ; IscS