Nicolas Duraffourg
NMR determination of a structure of a protein involved in the biosynthesis of Fe-S clusters: SufA
Published on 21 December 2006
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Thesis presented December 21, 2006
Abstract:
The SufA protein from
Escherichia coli is a homodimeric scaffold protein, allowing the formation of iron-sulfur clusters [Fe-S] before forwarding them to a target protein. This protein belongs to the SUF (for sulfur mobilization) operon which appears to be activated under oxidative stress. In order to have a better understanding of the coordination of the [Fe-S] by the SufA protein, we undertook the determination of the three-dimensional structure by nuclear magnetic resonance (NMR). Currently, we achieved on the monomeric form of the apo-protein. Preliminary results with the reconstituted [Fe-S] protein are also presented in this document. We were able to observe the presence of three cysteine residues whose role, which was determinate by biochemical studies, is to stabilize the [Fe-S] cluster. However the exact coordination of the [Fe-S] cluster by these cysteines is not well known. The structure resolution of the dimer (in progress), and complementary NMR studies on the holoprotein SufA should bring a better understanding of the coordination mode of its cluster. It is worth to note that structural differences, with regard to the X-ray structures (published during this thesis) were observed, located particularly in the C-terminal sequence who we find two over the three coordinating cysteines.
Keywords:
NMR, structure, metalloenzyme
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