Effects of linear amphiphilicity on membrane interactions of C-terminal thrombin peptides

Abstract

Link to publicationCitation for published version (APA): Singh, S., Papareddy, P., Kalle, M., Schmidtchen, A., & Malmsten, M. (2014). Effects of linear amphiphilicity on membrane interactions of C-terminal thrombin peptides. RSC Advances, 4(71), 37582-37591. DOI: 10.1039/c4ra05420bGeneral rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal AbstractEffects of linear amphiphilicity on membrane interactions of antimicrobial peptides were investigated by ellipsometry, dual polarization interferometry, fluorescence spectroscopy, light scattering, and circular dichroism. In doing so, the thrombinderived GKY25 (GKYGFYTHVFRLKKWIQKVIDQFGE) was compared to WFF25(WFFFYYLIIGGGVVTHQQRKKKKDE) of identical composition, but with amino acids sorted according to hydrophobicity, the latter peptide thus displaying pronounced linear amphiphilicity. In addition, GKY25dwith identical sequence but with selected D-amino acid substitutions) was included as a control peptide, for which conformationally induced (helix-related) amphiphilicity was suppressed. Through its pronounced linear amphiphilicity, WFF25, but not the less amphiphilic GKY25 and GKY25d, forms aggregates in solution. Through its terminal W/F stretch, WFF25 also displays pronounced selectivity, with higher membrane binding and liposome rupture than GKY25 and GKY25d for anionic membranes, but suppressed peptide insertion and lytic effects for zwitterionic ones. In addition, WFF25 binds extensively to anionic polyelectrolyte components in bacterial membranes, i.e., lipopolysaccharide and lipoteichoic acid, resulting in reduced antimicrobial effects through peptide scavenging, not seen for the less amphiphilic GKY25 and GKY25d peptides. Taken together, the results thus demonstrate a series of striking effects for highly amphiphilic peptides, which need to be recognized in the development of such compounds as potential peptide therapeutics.3

The Thrombin-Derived Host Defense Peptide GKY25 Inhibits Endotoxin-Induced Responses through Interactions with Lipopolysaccharide and Macrophages/Monocytes

“…2A). In contrast, the peptide WFF25, which binds LPS with higher affinity than GKY25 (17,33,34), and IVE25, which is derived from the N terminus of thrombin and does not bind LPS, did not block NF-kB/AP-1 activation (Fig. 2A).…”

Structural basis for endotoxin neutralisation and anti-inflammatory activity of thrombin-derived C-terminal peptides

“…Motivated by previously reported preferential binding of TCP to LPS over lipid membranes 21 , 56 , as well as the focus on LPS interactions in the present investigation, LPS micelles were chosen for these studies. It should be noted, however, that TCPs adopt similar conformation in other frequently used membrane-mimetic systems, indicating peptide conformation to depend relatively weakly on curvature and membrane headgroup (Supplementary Figure 14 ).…”

(Lipo)polysaccharide interactions of antimicrobial peptides

“…(WFFFYYLIIGGGVVTHQQRKKKKDE), with identical composition but with amino acids sorted according to hydrophobicity, thus displaying pronounced linear amphiphilicity, i.e., a gradient in hydrophobicity when going from one end of the peptide to the other (Figure 2b) (12).…”