2M80: Solution structure of yeast dithiol glutaredoxin Grx8

Citation:
Abstract
Glutaredoxins (Grxs) are wide-spread oxidoreductases that are found in all kingdoms of life. The yeast Saccharomyces cerevisiae encodes eight Grxs, among which, Grx8 shares a sequence identity of 30 and 23% with typical dithiol Grx1 and Grx2, respectively, but it exhibits a much lower GSH-dependent oxidoreductase activity. To elucidate its catalytic mechanism, we solved the solution structure of Grx8, which displays a typical Grx fold. Structural analysis indicated that Grx8 possesses a negatively charged CXXC motif (Cys(33)-Pro(34)-Asp(35)-Cys(36)) and a GSH-recognition site, which are distinct from Grx1 and Grx2. Subsequent structure-guided site mutations revealed that the D35Y single mutant and N80T/L81V double mutant possess increased activity of 10- and 11-fold, respectively; moreover, the D35Y/N80T/L81V triple mutant has increased activity of up to 44-fold, which is comparable to that of canonical Grx. Biochemical analyses suggested that the increase in catalytic efficiency resulted from a decreased pKa value of catalytic cysteine Cys33 and/or enhancement of the putative GSH-recognition site. Moreover, NMR chemical shift perturbation analyses combined with GSH analogue inhibition assays enabled us to elucidate that wild-type Grx8 and all mutants adopt a ping-pong mechanism of catalysis. All together, these findings provide structural insights into the catalytic mechanism of dithiol Grxs.
PDB ID: 2M80Download
MMDB ID: 119507
PDB Deposition Date: 2013/5/2
Updated in MMDB: 2018/05
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Biological Unit for 2M80: monomeric; determined by author
Molecular Components in 2M80
Label Count Molecule
Protein (1 molecule)
1
Glutaredoxin-8(Gene symbol: GRX8)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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