Protein Folding in the Presence of Water‐Soluble Cyclic Diselenides with Novel Oxidoreductase and Isomerase Activities

Abstract

The protein disulfide isomerase (PDI) family, found in the endoplasmic reticulum (ER) of the eukaryotic cell, catalyzes the formation and cleavage of disulfide bonds and thereby helps in protein folding. A decrease in PDI activity under ER stress conditions leads to protein misfolding, which is responsible for the progression of various human diseases, such as Alzheimer's, Parkinson's, diabetes mellitus, and atherosclerosis. Here we report that water-soluble cyclic diselenides mimic the multifunctional activity of the PDI family by facilitating oxidative folding, disulfide formation/reduction, and repair of the scrambled disulfide bonds in misfolded proteins.

Modeling Thioredoxin Reductase‐Like Activity with Cyclic Selenenyl Sulfides: Participation of an NH⋅⋅⋅Se Hydrogen Bond through Stabilization of the Mixed Se−S Intermediate

“…In the case of diselenides 1a/b,h owever,t he Se À species is formed by the first attack of the thiol to the diselenide (SeÀSe) bond. [13] Thus, the diselenide compounds would have exhibited ag reater catalytic activity than selenenyl sulfides 2 and 3.…”

“…The assay was performed by following al iterature protocol with slight modifications. [13] At est solution (2.8 mL) was prepared by mixing a2 00 mm phosphate/5 mm EDTAb uffer solution (2655 mL) at pH 7.5 that contained NADPH (1.12 mmol) and GSH (34.4 mmol) with aG Rs olution (145 mL, 255 UmL À1 ). An aliquot (300 mL) of the test solution was mixed with ac atalyst solution (50 mL, 900 mm)i n phosphate buffer (200 mm)a tp H7.5 and the phosphate buffer solution (550 mL) in a1 .5 mL microtube.…”

Revisiting the Formation of a Native Disulfide Bond: Consequences for Protein Regeneration and Beyond

“…To initiate oxidative folding, the protein of interest is first introduced into a reducing and unfolding buffer (6 M GdnHcl, 5 mM DTT red , 100 mM Tris-HCl, 1 mM EDTA pH 8) for a period of ~10-30 min [26,35,36,41,44,52]. The reducing and denaturing agents are separated from the now fully reduced and unfolded protein (R) using column chromatography or dialysis (against a low pH buffer which prevents acquisition of disulfide bonds).…”

“…It can best be described as a statistical coil. This is because hydrophobic interactions along During regeneration, the fully reduced polypeptide is observed to undergo gradual oxidation via thiol-disulfide exchange reactions with the help of external redox reagents such as glutathione (GSSG/GSH), dithiothrreitol (DTT ox /DTT red ), molecular oxygen or other synthetic catalysts, including those derived from selenium [29][30][31][32][33][34][35][36][37][38][39][40]. During this process, a number of intermediate species that vary in the number of their disulfide bonds are observed in the oxidative folding landscape [4][5][6]41].…”

Crystal structures of 4,4′-(disulfane-1,2-diyl)bis(5-methyl-2H-1,3-dithiol-2-one) and 4,4′-(diselanane-1,2-diyl)bis(5-methyl-2H-1,3-dithiol-2-one)

“…A diselenide from selenocysteins was shown to be structurally very similar to the respective disulfide from two cysteins (Gö rbitz et al, 2015). As a consequence, disulfide and diselenide compounds were developed as catalysts for oxidative protein folding and refolding reactions (Arai et al, 2018). Here we report the serendipitous synthesis and structural characterization of bis[3-methyl-1,3-ene-dithiol-2-one] disulfide and bis[3-methyl-1,3-ene-dithiol-2-one] diselenide via unprecedented routes.…”