Effects of N- and C-terminal truncation of HP (2-20) from Helicobacter pylori ribosomal protein L1 (RPL1) on its anti-microbial activity.

HP (2-20) [derived from the N-terminal region of Helicobacter pylori Ribosomal Protein L1 (RPL1)], a 19-mer peptide, possesses broad-spectrum anti-microbial activity. As the N- (residues 2-3) and C-terminal (residues 14-20) residues can be deleted without affecting antimicrobial activity, we have now determined the minimum chain length necessary for the retention of antimicrobial activity, and its mode of action. The N- (residues 2-3) and C-terminal (residues 17-20) truncated fragments [HP (4-16)] induce increased antibiotic activity against several bacterial strains without hemolysis. Flow cytometric analysis, scanning electron microscopy and fluorescence confocal microscopy revealed that HP (4-16) acted rapidly on the plasma membranes of the fungal cells in a salt- and energy-independent manner.