A plausible role of salivary copper in antimicrobial activity of histatin-5—Metal binding and oxidative activity of its copper complex

Histatin-5 (Hn5) is an antimicrobial salivary peptide of 24 amino acids. Two specific metal-binding sites were revealed with electronic, NMR, and EPR spectroscopy. The complex Cu2II–Hn5 effectively oxidizes catechol, exhibiting enzyme-like kinetics (kcat = 0.011 and 0.060 s−1 and kcat/Km = 19 and 50 M−1 s−1 without and with 12.8 mM H2O2, respectively). The significant oxidative activity may contribute to the biological activity of this antibiotic metallopeptide.

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