dithiolglutaredoxiner

Dithiolglutaredoxiner are a proposed group of redox-active enzymes related to the glutaredoxin family, distinguished by a dithiol active site that contains two catalytic cysteine residues. They are thought to catalyze thiol-disulfide exchange reactions in a glutathione-dependent manner, contributing to the maintenance of cellular redox balance and the regulation of protein thiol status. The term is used to differentiate them from monothiol glutaredoxins, which have a single catalytic cysteine.

Structural features of dithiolglutaredoxiner are consistent with a compact, thioredoxin-like fold commonly seen in glutaredoxins. Most members would be small proteins, typically in the order of 80 to 150 amino acids, and would harbor an active-site motif such as Cys-X-X-Cys, enabling formation and resolution of transient disulfide bonds during catalysis. In the catalytic cycle, the enzyme alternates between reduced and oxidized forms, with reduced glutathione (GSH) serving as a reducing partner and oxidized glutathione (GSSG) regenerated in the process.

Functions and roles attributed to dithiolglutaredoxiner include deglutathionylation of protein substrates, repair of oxidatively damaged disulfides, and, in some contexts, involvement in the assembly or delivery of iron-sulfur clusters. They are considered to occur across diverse organisms, including bacteria, plants, and animals, and are often found in compartments where redox regulation is critical.

Research status: The concept of dithiolglutaredoxiner reflects ongoing efforts to classify the diversity of glutaredoxin-like proteins. Current studies focus on substrate specificity, interactions with the glutathione redox couple (GSH/GSSG), and physiological roles in stress responses and cellular signaling. See also glutaredoxin, thioredoxin, and redox regulation.