Periodical
The Escherichia coliBolA Protein IbaG Forms a Histidine-Ligated [2Fe-2S]-Bridged Complex with Grx4
| العنوان: | The Escherichia coliBolA Protein IbaG Forms a Histidine-Ligated [2Fe-2S]-Bridged Complex with Grx4 |
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| المؤلفون: | Dlouhy, Adrienne C., Li, Haoran, Albetel, Angela-Nadia, Zhang, Bo, Mapolelo, Daphne T., Randeniya, Sajini, Holland, Ashley A., Johnson, Michael K., Outten, Caryn E. |
| المصدر: | Biochemistry; December 2016, Vol. 55 Issue: 49 p6869-6879, 11p |
| مستخلص: | Two ubiquitous protein families have emerged as key players in iron metabolism, the CGFS-type monothiol glutaredoxins (Grxs) and the BolA proteins. Monothiol Grxs and BolA proteins form heterocomplexes that have been implicated in Fe–S cluster assembly and trafficking. The Escherichia coligenome encodes members of both of these proteins families, namely, the monothiol glutaredoxin Grx4 and two BolA family proteins, BolA and IbaG. Previous work has demonstrated that E. coliGrx4 and BolA interact as both apo and [2Fe-2S]-bridged heterodimers that are spectroscopically distinct from [2Fe-2S]-bridged Grx4 homodimers. However, the physical and functional interactions between Grx4 and IbaG are uncharacterized. Here we show that co-expression of Grx4 with IbaG yields a [2Fe-2S]-bridged Grx4–IbaG heterodimer. In vitrointeraction studies indicate that IbaG binds the [2Fe-2S] Grx4 homodimer to form apo Grx4–IbaG heterodimer as well as the [2Fe-2S] Grx4–IbaG heterodimer, altering the cluster stability and coordination environment. Additionally, spectroscopic and mutagenesis studies provide evidence that IbaG ligates the Fe–S cluster via the conserved histidine that is present in all BolA proteins and by a second conserved histidine that is present in the H/C loop of two of the four classes of BolA proteins. These results suggest that IbaG may function in Fe–S cluster assembly and trafficking in E. colias demonstrated for other BolA homologues that interact with monothiol Grxs. |
| قاعدة البيانات: | Supplemental Index |
| تدمد: | 00062960 15204995 |
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| DOI: | 10.1021/acs.biochem.6b00812 |