Transformation of a Mononitrosyl Iron Complex to a [2Fe-2S] Cluster by a Cysteine Analogue

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• 作者：Jessica Fitzpatrick ; Harris Kalyvas ; Milos R. Filipovic ; Ivana Ivanovi膰-Burmazovi膰 ; John C. MacDonald ; Jason Shearer ; Eunsuk Kim
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：May 21, 2014
• 年：2014
• 卷：136
• 期：20
• 页码：7229-7232
• 全文大小：223K
• 年卷期：v.136,no.20(May 21, 2014)
• ISSN：1520-5126

文摘

Reversible modification of iron-sulfur clusters by nitric oxide acts as a genetic switch in a group of regulatory proteins. While the conversion of [Fe-S] clusters to iron-nitrosyls has been widely studied in the past, little is known about the reverse process, the repair of [Fe-S] clusters. Reported here is a system in which a mononitrosyl iron complex (MNIC), (PPN)[Fe(S^tBu)₃(NO)] (1), is converted to a [2Fe-2S] cluster, (PPN)₂[Fe₂S₂(SCH₂CH₂C(O)OMe)₄] (2). This conversion requires only the addition of a cysteine analogue, 3-mercaptomethylpropionate (MMP), at room temperature without the need for any other reagents. The identity of 2 was confirmed spectroscopically, chemically, crystallographically, and analytically. Mass spectrometry and ³⁴S labeling studies support that the bridging sulfides in 2 derive from the added MMP, the cysteine analogue. The NO lost during the conversion of 1 to 2 is trapped in a dinitrosyl iron side product, (PPN)[Fe(SCH₂CH₂C(O)OMe)₂(NO)₂] (4). The present system implies that MNICs are likely intermediates in the repair of NO-damaged [2Fe-2S] clusters and that cysteine is a viable molecule responsible for the destabilization of MINCs and the formation of [2Fe-2S] clusters.