Syntheses and structural characterization of water-soluble selenium reagents for the redox control of protein disulfide bonds

Abstract

A new class of water-soluble redox reagents (1-4) that contain selenium as the active site was developed for the purpose of the redox control of protein structures. The X-ray crystallographic analyses revealed that trans-3,4-dihydroxy-1-selenolane (DHSred) (1) and its Se-oxide (DHSox) (2) have two axial hydroxy groups on the selenolane five-membered ring, whereas trans-1,2-diselenane-4,5-diol (DSTox) (3), a selenium analog of oxidized dithiothreitol (DTTox), has two equatorial hydroxy groups on the diselenane six-membered ring. According to the vicinal 3JHH coupling constants observed for 1-3, it was suggested that they adopt similar structures in solution to those in the solid state. Diselenothreitol (DSTred) (4), a selenium analog of dithiothreitol (DTTred), was also synthesized, but it was too air sensitive to be isolated. The reactions of 1-4 with DTTox and DTTred indicated that the oxidizing power of DHSox (2) exceeds by far that of DTTox, while the reducing power of DSTred (4) exceeds that of DTTred.