1z7r
From Proteopedia
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Solution Structure of reduced glutaredoxin C1 from Populus tremula x tremuloides
Overview
Glutaredoxins are glutathione-dependent enzymes that function to reduce, disulfide bonds in vivo. Interestingly, a recent discovery indicates that, some glutaredoxins can also exist in another form, an iron-sulfur protein, [Lillig, C. H., et al. (2005) Proc. Natl. Acad. Sci. U.S.A. 102, 8168-8173]. This provides a direct connection between glutaredoxins and, iron-sulfur proteins, suggesting a possible new regulatory role of, iron-sulfur clusters along with the new functional switch of, glutaredoxins. Biochemical studies have indicated that poplar glutaredoxin, C1 (Grx-C1) is also such a biform protein. The apo form (monomer) of, Grx-C1 is a regular glutaredoxin, and the holo form (dimer) is an, iron-sulfur protein with a bridging [2Fe-2S] cluster. Here, we report the, structural characterizations of poplar Grx-C1 in both the apo and holo, forms by NMR spectroscopy. The solution structure of the reduced apo, Grx-C1, which is the first plant Grx structure, shows a typical Grx fold., When poplar Grx-C1 forms a dimer with an iron-sulfur cluster, each subunit, of the holo form still retains the overall fold of the apo form. The, bridging iron-sulfur cluster in holo Grx-C1 is coordinated near the active, site. In addition to the iron-sulfur cluster linker, helix alpha3 of each, subunit is probably involved in the direct contact between the two, subunits. Moreover, two glutathione molecules are identified in the, vicinity of the iron-sulfur cluster and very likely participate in cluster, coordination. Taken together, we propose that the bridging [2Fe-2S], cluster is coordinated by the first cysteine at the glutaredoxin active, site from each subunit of holo Grx-C1, along with two cysteines from two, glutathione molecules. Our studies reveal that holo Grx-C1 has a novel, structural and iron-sulfur cluster coordination pattern for an iron-sulfur, protein.
About this Structure
1Z7R is a Single protein structure of sequence from Populus tremula x populus tremuloides. Full crystallographic information is available from OCA.
Reference
Structural insight into poplar glutaredoxin C1 with a bridging iron-sulfur cluster at the active site., Feng Y, Zhong N, Rouhier N, Hase T, Kusunoki M, Jacquot JP, Jin C, Xia B, Biochemistry. 2006 Jul 4;45(26):7998-8008. PMID:16800625
Page seeded by OCA on Sun Nov 25 04:46:31 2007
