Novel histone-derived antimicrobial peptides use different antimicrobial mechanisms

Abstract

The increase in multidrug resistant bacteria has sparked an interest in the development of novel antibiotics. Antimicrobial peptides (AMPs) that operate by crossing the cell membrane may also have the potential to deliver drugs to intracellular targets. Buforin 2 (BF2) is an AMP that shares sequence identity with a fragment of histone subunit H2A and whose bactericidal mechanism depends on membrane translocation and DNA binding. Previously, novel histone-derived antimicrobial peptides (HDAPs) were designed based on properties of BF2, and DesHDAP1 and DesHDAP3 showed significant antibacterial activity. In this study, their DNA binding, permeabilization, and translocation abilities were assessed independently and compared to antibacterial activity to determine whether they share a mechanism with BF2. To investigate the importance of proline in determining the peptides' mechanisms of action, proline to alanine mutants of the novel peptides were generated. DesHDAP1, which shows significant similarities to BF2 in terms of secondary structure, translocates effectively across lipid vesicle and bacterial membranes, while the DesHDAP1 proline mutant shows reduced translocation abilities and antimicrobial potency. In contrast, both DesHDAP3 and its proline mutant translocate poorly, though the DesHDAP3 proline mutant is more potent. Our findings suggest that a proline hinge can promote membrane translocation in some peptides, but that the extent of its effect on permeabilization depends on the peptide's amphipathic properties. Our results also highlight the different antimicrobial mechanisms exhibited by histone-derived peptides and suggest that histones may serve as a source of novel AMPs with varied properties.

Bacterial Spheroplasts as a Model for Visualizing Membrane Translocation of Antimicrobial Peptides

“…Thus, it has become increasingly important for researchers to reliably determine whether AMPs are able to effectively translocate into bacterial cells (3). Many researchers have turned to confocal microscopy in order to assess cell entry (4)(5)(6)(7)(8)(9)(10)(11). However, bacterial cells are so small that effective imaging is limited by the resolution of conventional light microscopes.…”

A prawn core histone 4: Derivation of N- and C-terminal peptides and their antimicrobial properties, molecular characterization and mRNA transcription

“…Overall, the results indicate increased antimicrobial activity of peptides against Gram-negative bacteria than the Gram-positive bacteria. In respect to the peptides, VVY15 peptide produced better activity than the KVL22 peptide which may due to the following reasons: Pavia et al (2012), Lee et al (2007), Thennarasu and Nagaraj (1996) and Zhang et al (1999) reported that the presence of proline in the AMPs decreased the ability of permeabilization, because proline disrupts the ␣-helical structures. In our study also, we observed a proline (P 33 ) residue in the KVL21-synthesized peptide, while proline amino acid is absent in VVY15 peptide.…”

“…In this case, MrH4 mRNA received −105.9 kcal/mol as MFE value, hence it is plausible to suggest that the nucleotides of MrH4 mRNA are almost properly paired and only a few nucleotides are left unpaired, thus showing the stability of MrH4 mRNA. According to the available literature (Pavia et al 2012;Torrent et al 2012 KVL22 and VVY15 indicates antimicrobial activity of MrH4 peptides. Moreover, the presence of cationic amino acids including arginine and lysine showed a net positive charge, which is necessary for an AMP (Boman 2003;Nam et al 2012).…”

“…Two peptide sequences (N-terminal peptide: 21 KVLRDNIQGITKPAIRRLARRG 42 and C-terminal peptide: 87 VVYALKRQGRTLYGF 101 ) were predicted to be having antimicrobial activity based upon the sequence conservation in most species and presence of the AMPs characteristic signature from MrH4 protein sequence at N and C terminals (Pavia et al 2012). Hereafter, the peptide derived from N-terminal region will be denoted as KVL22 and the C-terminal region peptide as VVY15.…”

<b><i>Streptococcus pyogenes</i></b> Escapes Killing from Extracellular Histones through Plasminogen Binding and Activation by Streptokinase

“…Thereby, plasmin activity is generated on the streptococcal surface and involved in invasive spread by degrading fibrin clots, components of the extracellular matrix and antimicrobial peptides [11,14]. It has been shown that plasmin cleaves histones in vitro [15], and it is assumed that histones operate by disintegrating or penetrating the bacterial membrane [16,17]. We therefore speculated that plasminogen acquisition at the streptococcal surface might serve as a survival strategy of GAS in an environment with high local concentrations of extracellular histones.…”