temporin and indolicidin

Quorum Quenching (QQ) enzymes can be used to prevent bacterial antibiotic resistance by degradation of Quorum Sensing (QS) signaling molecules, for example N-acyl homoserine lactones (AHLs). This paper is aimed at the in silico investigation of the possible combinations of hexahistidine-tagged organophosphorus hydrolase (His

Topics: Acyl-Butyrolactones; Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Aryldialkylphosphatase; Histidine; Hydrolysis; Models, Molecular; Molecular Docking Simulation; Nanocomposites; Oligopeptides; Peptides; Polyelectrolytes; Proteins; Quorum Sensing

The effects of oxidatively modified phospholipids on the association with model biomembranes of four antimicrobial peptides (AMPs), temporin B and L, indolicidin, and LL-37(F27W) were studied by Langmuir balance and fluorescence spectroscopy. In keeping with previous reports the negatively charged phospholipid phosphatidylglycerol (PG) enhanced the intercalation of all four peptides into lipid monolayers and liposomal bilayers under low ionic strength conditions. Interestingly, similar effect was observed for 1-palmitoyl-2-(9'-oxo-nonanoyl)-sn-glycero-3-phosphocholine (PoxnoPC), a zwitterionic oxidized phospholipid bearing an aldehyde function at the end of its truncated sn-2 acyl chain. Instead, the structurally similar 1-palmitoyl-2-azelaoyl-sn-glycero-3-phosphocholine (PazePC) containing a carboxylic moiety was less efficient in promoting the membrane association of these peptides. Physiological saline reduced the binding of the above peptides to membranes containing PG, whereas interactions with PoxnoPC were found to be insensitive to ionic strength. Notably, membrane intercalation of temporin L, the most surface active of the above peptides could be into PoxnoPC containing monolayers was strongly attenuated by methoxyamine, suggesting the importance of Schiff base formation between peptide amino groups and the lipid aldehyde function. PoxnoPC and similar aldehyde bearing oxidatively modified phospholipids could represent novel molecular targets for AMPs.

Topics: Animals; Anti-Infective Agents; Antimicrobial Cationic Peptides; Buffers; Cathelicidins; Humans; Liposomes; Oxidation-Reduction; Peptides; Phospholipids; Proteins

The antimicrobial peptides magainin 2, indolicidin, and temporins B and L were found to modulate the hydrolytic activity of secretory phospholipase A(2) (sPLA(2)) from bee venom and in human lacrimal fluid. More specifically, hydrolysis of phosphatidylcholine (PC) liposomes by bee venom sPLA(2) at 10 micro M Ca(2+) was attenuated by these peptides while augmented product formation was observed in the presence of 5 mM Ca(2+). The activity of sPLA(2) towards anionic liposomes was significantly enhanced by the antimicrobial peptides at low [Ca(2+)] and was further enhanced in the presence of 5 mM Ca(2+). Similarly, with 5 mM Ca(2+) the hydrolysis of anionic liposomes was enhanced significantly by human lacrimal fluid sPLA(2), while that of PC liposomes was attenuated. These results indicate that concerted action of antimicrobial peptides and sPLA(2) could improve the efficiency of the innate response to infections. Interestingly, inclusion of a cationic gemini surfactant in the vesicles showed an essentially similar pattern on sPLA(2) activity, suggesting that the modulation of the enzyme activity by the antimicrobial peptides may involve also charge properties of the substrate surface.

Topics: Animals; Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Bee Venoms; Bees; Chelating Agents; Drug Synergism; Edetic Acid; Group II Phospholipases A2; Humans; Hydrolysis; In Vitro Techniques; Liposomes; Magainins; Phospholipases A; Phospholipases A2; Proteins; Surface-Active Agents; Tears; Xenopus Proteins