Metformin bound to HMGB1 through its acidic tail.
A, domain structure of HMGB1 and its mutants used in this study. B, purified His-tagged HMGB1 and its mutants were pulled down with the metformin beads and detected by immunoblotting with anti-His antibody. I, input (30%); C, control beads; M, metformin beads. C, full-length HMGB1 was pulled down with the metformin beads in the presence of the indicated concentrations of the acidic tail or HMGB1-ΔAT. Data shown are representative of three independent experiments with similar results.