FIG. 3.

Different redox states of HMGB1. HMGB1 is found in three different oxidation states: reduced HMGB1 (with Cys23, Cys45, and Cys106 residues in the thiol state), “disulfide HMGB1” (with an intramolecular disulfide bond between Cys23 and Cys45), and “sulfonic HMGB1” (with all three cysteines in the hyperoxidized sulfonic acid state). Reduced HMGB1 exhibits chemokine-like function, disulfide HMGB1 promotes cytokine production, whereas in contrast, sulfonic HMGB1 does not exert any immunological function. HMGB1, high mobility group box 1.