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Research

Amino acid residues 201-205 in C-terminal acidic tail region plays a crucial role in antibacterial activity of HMGB1

Wei Gong^* , Yuan Li^* , Fan Chao , Gang Huang and Fengtian He

Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, PR China

author email corresponding author email* Contributed equally

Journal of Biomedical Science 2009, 16:83doi:10.1186/1423-0127-16-83

Published:	14 September 2009

Abstract

Background

Antibacterial activity is a novel function of high-mobility group box 1 (HMGB1). However, the functional site for this new effect is presently unknown.

Methods and Results

In this study, recombinant human HMGB1 A box and B box (rHMGB1 A box, rHMGB1 B box), recombinant human HMGB1 (rHMGB1) and the truncated C-terminal acidic tail mutant (tHMGB1) were prepared by the prokaryotic expression system. The C-terminal acidic tail (C peptide) was synthesized, which was composed of 30 amino acid residues. Antibacterial assays showed that both the full length rHMGB1 and the synthetic C peptide alone could efficiently inhibit bacteria proliferation, but rHMGB1 A box and B box, and tHMGB1 lacking the C-terminal acidic tail had no antibacterial function. These results suggest that C-terminal acidic tail is the key region for the antibacterial activity of HMGB1. Furthermore, we prepared eleven different deleted mutants lacking several amino acid residues in C-terminal acidic tail of HMGB1. Antibacterial assays of these mutants demonstrate that the amino acid residues 201-205 in C-terminal acidic tail region is the core functional site for the antibacterial activity of the molecule.

Conclusion

In sum, these results define the key region and the crucial site in HMGB1 for its antibacterial function, which is helpful to illustrating the antibacterial mechanisms of HMGB1.