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 Cu-2(II)-Hn5 effectively oxidizes catechol, exhibiting enzyme-like kinetics (k(cat) = 0.011 and 0.060 s(1) and k(cat)/K-m = 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. (C) 2009 Elsevier Ltd. All rights reserved.