Fuscopeptins, antimicrobial lipodepsipeptides from Pseudomonas fuscovaginae, are channel forming peptides active on biological and model membranes.
FP-A and FP-B are LDPs produced by the plant pathogen Pseudomonas fuscovaginae. As expected from their primary structure, they shared a similar mechanism of action with the better characterized SPs, synthesized by strains of Pseudomonas syringae pv. syringae. Indeed, they displayed hemolytic activity on human erythrocytes and were able to induce calcein release from LUVs: the effect was dependent on the concentration of the FPs and the lipid composition of the liposome and, in particular, it increased with the SM content of the membrane. The permeabilizing activity was further investigated on PLMs. FPs were able to open pores on pure POPC membranes. Pore opening was strongly voltage dependent: by switching the potential from negative to positive values, an increase in the absolute amplitude of transmembrane current was induced with simultaneous closure of pores. In 0.1 M KCl both FPs' pores had a conductance of 4 and 9 pS at - 140 mV and + 140 mV, respectively. Studies on ion selectivity indicated that FPs formed cation-selective channels.
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FBK & CNR Istituto di Biofisica, via alla Cascata 56/C, I-38100 Povo (Trento), Italy.
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Dalla Serra
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D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000737:chemistry*; D004912:Erythrocytes / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015640:Ion Channel Gating / Q000187:drug effects; D007473:Ion Channels / Q000737:chemistry / Q000187:drug effects; D008051:Lipid Bilayers / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry; D008567:Membranes, Artificial; D008954:Models, Biological; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000502:physiology*; D011549:Pseudomonas / Q000737:chemistry / Q000235:genetics / Q000472:pathogenicity*; D013329:Structure-Activity Relationship
D000890:Anti-Infective Agents; D007473:Ion Channels; D008051:Lipid Bilayers; D008081:Liposomes; D008567:Membranes, Artificial; D010456:Peptides, Cyclic