Interactions of an antimicrobial peptide, tachyplesin I, with lipid membranes

Solution and Micelle-Bound Structures of Tachyplesin I and Its Active Aromatic Linear Derivatives,

“…There is, in fact, considerable evidence that tachyplesin inserts into and transverses membranes (6,7,40). Matsuzaki et al (6) have proposed a mechanism for membrane permeabilization by tachyplesin I based upon data from RET experiments on chromophore-labeled vesicles and on cross-membrane conductance measurements on planar bilayers.…”

Novel Expression System for Large-Scale Production and Purification of Recombinant Class IIa Bacteriocins and Its Application to Piscicolin 126

“…K ϩ concentrations were measured at 5-s intervals by using a K ϩ ion-selective electrode with an internal reference (Orion Research, Boston, Mass.). Cells of L. monocytogenes 4A from an overnight culture were collected by centrifugation (4,000 ϫ g, 15 min, 4°C), washed twice in a 10% volume of the standard K ϩ buffer (10 mM KCl, 0.2% glucose, 50 mM NaH 2 PO 4 ⅐ Na 2 HPO 4 [pH 6.70]), resuspended to a final OD 600 of 18 (approximately 2.4 ϫ 10 10 cells/ml), and stored on ice for periods no longer than 4 h. Where appropriate, cells were resuspended to 2 ml in buffers of defined pH (pH 5.74, 6.40, 6.70, 7.02, and 7.66) or NaCl concentration (25,50,150, and 300 mM). Cells were equilibrated to 25°C, and K ϩ concentrations in the buffer were determined.…”

“…Class IIa bacteriocins are active at the cell membranes of gram-positive organisms, and their limited spectrum of activity is attributed to the requirement for a specific receptor interaction on the target cell (11,12,16,17,34,38). Class IIa bacteriocins cause the efflux of accumulated compounds and ions (1,5,8,25,39), a dissipation of the membrane potential (1), and depletion of ATP (8), thereby preventing growth of the organism.A requirement for the continued improvement of structurefunction models of class IIa bacteriocins through biophysical studies is the production and purification of large quantities (up to 10 mg) of bacteriocin. Bacteriocin production systems currently utilized include expression in the native strain (19,21), recombinant expression systems in LAB (3, 24), recombinant expression by use of Escherichia coli (27,28), and chemical synthesis (15, 37).…”

“…Class IIa bacteriocins are active at the cell membranes of gram-positive organisms, and their limited spectrum of activity is attributed to the requirement for a specific receptor interaction on the target cell (11,12,16,17,34,38). Class IIa bacteriocins cause the efflux of accumulated compounds and ions (1,5,8,25,39), a dissipation of the membrane potential (1), and depletion of ATP (8), thereby preventing growth of the organism.…”

Cationic Peptide Interactions with Biological Macromolecules

“…While evidence indicates that tachyplesin interacts with lipid membranes and kills bacteria by leakage, the exact mechanism of leakage and killing remains poorly defined [47]. Tachyplesin I is a cyclic broad-spectrum antimicrobial peptide with a rigid, antiparallelsheet and two intramolecular S-S linkages [46].…”