title: Galleria mellonella native and analogue peptides Gm1 and ΔGm1. I) biophysical characterization of the interaction mechanisms with bacterial model membranes.
abstract: Natural occurring antimicrobial peptides (AMPs) are important components of the innate immune system of animals and plants. They are considered to be promising alternatives to conventional antibiotics. Here we present a comparative study of two synthetic peptides: Gm1, corresponding to the natural overall uncharged peptide from Galleria mellonella (Gm) and ΔGm1, a modified overall positively charged Gm1 variant. We have studied the interaction of the peptides with lipid membranes composed of different kinds of lipopolysaccharides (LPS) and dimyristoylphosphatidylglycerol (DMPG), in some cases also dimyristoylphosphatidylethanolamine (DMPE) as representative lipid components of Gram-negative bacterial membranes, by applying Fourier-transform infrared spectroscopy (FTIR), Förster resonance energy transfer spectroscopy (FRET), differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC). Gm1 generates a destabilizing effect on the gel to liquid crystalline phase transition of the acyl chains of the lipids, as deduced from a decrease in the phase transition temperature and enthalpy, suggesting a fluidization, whereas ΔGm1 led to the opposite behavior. Further, FTIR analysis of the functional groups of the lipids participating in the interaction with the peptides indicated a shift in the band position and intensity of the asymmetric PO2(-) stretching vibration originating from the lipid phosphate groups, a consequence of the sterical changes in the head group region. Interestingly, FRET spectroscopy showed a similar intercalation of both peptides into the DMPG and LPS, but much less into the DMPE membrane systems. These results are discussed in the light of a possible use of the peptides as antimicrobial and anti-endotoxin drugs.
authors.affiliation: Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, AA. 1226 Medellín, Colombia. Electronic address: wilcova@gmail.com.
authors.forename: Wilmar
authors.initials: W
authors.lastname: Correa
authors.affiliation: Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, AA. 1226 Medellín, Colombia. Electronic address: mmanriqm@exactas.udea.edu.co.
authors.forename: Marcela
authors.initials: M
authors.lastname: Manrique-Moreno
authors.affiliation: Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, AA. 1226 Medellín, Colombia. Electronic address: epatino@matematicas.udea.edu.co.
authors.forename: Edwin
authors.initials: E
authors.lastname: Patiño
authors.affiliation: Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, AA. 1226 Medellín, Colombia. Electronic address: directorgiem@gmail.com.
authors.forename: Carlos
authors.initials: C
authors.lastname: Peláez-Jaramillo
authors.affiliation: Forschungszentrum Borstel, LG Biophysik, D-23845 Borstel, Germany. Electronic address: ykaconis@fz-borstel.de.
authors.forename: Yani
authors.initials: Y
authors.lastname: Kaconis
authors.affiliation: Forschungszentrum Borstel, LG Biophysik, D-23845 Borstel, Germany. Electronic address: tgutsmann@fz-borstel.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gutsmann
authors.affiliation: Martin-Luther-University Halle/Wittenberg, Department of Chemistry/Physical Chemistry, D-06120 Halle/Saale, Germany. Electronic address: Patrick.Garidel@chemie.uni-halle.de.
authors.forename: Patrick
authors.initials: P
authors.lastname: Garidel
authors.affiliation: Forschungszentrum Borstel, LG Biophysik, D-23845 Borstel, Germany. Electronic address: lheinbockel@fz-borstel.de.
authors.forename: Lena
authors.initials: L
authors.lastname: Heinbockel
authors.affiliation: Forschungszentrum Borstel, LG Biophysik, D-23845 Borstel, Germany. Electronic address: kbrandenburg@fz-borstel.de.
authors.forename: Klaus
authors.initials: K
authors.lastname: Brandenburg
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry*; D001419:Bacteria / Q000737:chemistry*; D002462:Cell Membrane / Q000737:chemistry*; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry*; D019476:Insect Proteins / Q000737:chemistry*; D008567:Membranes, Artificial; D008956:Models, Chemical; D009036:Moths
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D019476:Insect Proteins; D008567:Membranes, Artificial; D004134:Dimyristoylphosphatidylcholine
keywords: Antimicrobial peptide; Attenuated total reflection; Cell membrane; Differential scanning calorimetry; Lipopolysaccharide; Peptide–lipid interaction